feat(files): default ctrl-g to toggle .gitignore

To disable: set `files.action["ctrl-g"]=false` or run:
```lua
:lua require("fzf-lua").files({ actions = { ["ctrl-g"]=false } })
```
Additional changes:
- Enabled git-delta auto-detection as pager for git
  status|commits|bcommits, to disable set `preview_pager=false`:
```lua
:lua require("fzf-lua").git_status({ preview_pager=false })
:FzfLua git_commits preview_pager=false
```

- Replaced `<file>` placeholders with `{file}` (backward compat)

README.md

@@ -684,12 +684,13 @@ require'fzf-lua'.setup {
       args            = nil,
     },
     git_diff = {
+      -- if required, use `{file}` for argument positioning
+      -- e.g. `cmd_modified = "git diff --color HEAD {file} | cut -c -30"`
       cmd_deleted     = "git diff --color HEAD --",
       cmd_modified    = "git diff --color HEAD",
       cmd_untracked   = "git diff --color --no-index /dev/null",
-      -- uncomment if you wish to use git-delta as pager
-      -- can also be set under 'git.status.preview_pager'
-      -- pager        = "delta --width=$FZF_PREVIEW_COLUMNS",
+      -- git-delta is automatically detected as pager, set `pager=false`
+      -- to disable, can also be set under 'git.status.preview_pager'
     },
     man = {
       -- NOTE: remove the `-c` flag when using man-db
@@ -720,8 +721,8 @@ require'fzf-lua'.setup {
         -- neovim terminal only supports `viu` block output
         ["png"]       = { "viu", "-b" },
         -- by default the filename is added as last argument
-        -- if required, use `<file>` for argument positioning
-        ["svg"]       = { "chafa", "<file>" },
+        -- if required, use `{file}` for argument positioning
+        ["svg"]       = { "chafa", "{file}" },
         ["jpg"]       = { "ueberzug" },
       },
       -- if using `ueberzug` in the above extensions map
@@ -742,8 +743,10 @@ require'fzf-lua'.setup {
     },
     codeaction_native = {
       diff_opts = { ctxlen = 3 },
-      pager     = vim.fn.executable("delta") == 1
-          and "delta --width=$FZF_PREVIEW_COLUMNS" or nil,
+      -- git-delta is automatically detected as pager, set `pager=false`
+      -- to disable, can also be set under 'lsp.code_actions.preview_pager'
+      -- recommended styling for delta
+      --pager = [[delta --width=$COLUMNS --hunk-header-style="omit" --file-style="omit"]],
     },
   },
   -- PROVIDERS SETUP
@@ -810,8 +813,8 @@ require'fzf-lua'.setup {
       git_icons     = true,
       color_icons   = true,
       previewer     = "git_diff",
-      -- uncomment if you wish to use git-delta as pager
-      --preview_pager = "delta --width=$FZF_PREVIEW_COLUMNS",
+      -- git-delta is automatically detected as pager, uncomment to disable
+      -- preview_pager = false,
       actions = {
         -- actions inherit from 'actions.files' and merge
         ["right"]  = { fn = actions.git_unstage, reload = true },
@@ -830,9 +833,9 @@ require'fzf-lua'.setup {
     commits = {
       prompt        = 'Commits❯ ',
       cmd           = "git log --color --pretty=format:'%C(yellow)%h%Creset %Cgreen(%><(12)%cr%><|(12))%Creset %s %C(blue)<%an>%Creset'",
-      preview       = "git show --pretty='%Cred%H%n%Cblue%an <%ae>%n%C(yellow)%cD%n%Cgreen%s' --color {1}",
-      -- uncomment if you wish to use git-delta as pager
-      --preview_pager = "delta --width=$FZF_PREVIEW_COLUMNS",
+      preview       = "git show --color {1}",
+      -- git-delta is automatically detected as pager, uncomment to disable
+      -- preview_pager = false,
       actions = {
         ["default"] = actions.git_checkout,
         -- remove `exec_silent` or set to `false` to exit after yank
@@ -843,13 +846,13 @@ require'fzf-lua'.setup {
       prompt        = 'BCommits❯ ',
       -- default preview shows a git diff vs the previous commit
       -- if you prefer to see the entire commit you can use:
-      --   git show --color {1} --rotate-to=<file>
+      --   git show --color {1} --rotate-to={file}
       --   {1}    : commit SHA (fzf field index expression)
-      --   <file> : filepath placement within the commands
-      cmd           = "git log --color --pretty=format:'%C(yellow)%h%Creset %Cgreen(%><(12)%cr%><|(12))%Creset %s %C(blue)<%an>%Creset' <file>",
-      preview       = "git diff --color {1}^! -- <file>",
-      -- uncomment if you wish to use git-delta as pager
-      --preview_pager = "delta --width=$FZF_PREVIEW_COLUMNS",
+      --   {file} : filepath placement within the commands
+      cmd           = "git log --color --pretty=format:'%C(yellow)%h%Creset %Cgreen(%><(12)%cr%><|(12))%Creset %s %C(blue)<%an>%Creset' {file}",
+      preview       = "git show --color {1} -- {file}",
+      -- git-delta is automatically detected as pager, uncomment to disable
+      -- preview_pager = false,
       actions = {
         ["default"] = actions.git_buf_edit,
         ["ctrl-s"]  = actions.git_buf_split,

lua/fzf-lua/defaults.lua

@@ -16,6 +16,10 @@ function M._default_previewer_fn()
   return type(previewer) == "function" and previewer() or previewer
 end
 
+function M._preview_pager_fn()
+  return vim.fn.executable("delta") == 1 and "delta --width=$FZF_PREVIEW_COLUMNS" or nil
+end
+
 M.defaults = {
   nbsp          = utils.nbsp,
   winopts       = {
@@ -162,6 +166,7 @@ M.defaults = {
       _ctor = previewers.fzf.head,
     },
     git_diff = {
+      pager         = M._preview_pager_fn,
       cmd_deleted   = "git diff --color HEAD --",
       cmd_modified  = "git diff --color HEAD",
       cmd_untracked = "git diff --color --no-index /dev/null",
@@ -199,9 +204,7 @@ M.defaults = {
     codeaction_native = {
       _ctor     = previewers.fzf.codeaction,
       diff_opts = { ctxlen = 3 },
-      pager     = function()
-        return vim.fn.executable("delta") == 1 and "delta --width=$FZF_PREVIEW_COLUMNS" or nil
-      end,
+      pager     = M._preview_pager_fn,
     },
   },
 }
@@ -224,7 +227,7 @@ M.defaults.files = {
   fd_opts                = "--color=never --type f --hidden --follow --exclude .git",
   toggle_ignore_flag     = "--no-ignore",
   _actions               = function() return M.globals.actions.files end,
-  -- actions                = { ["ctrl-g"] = { actions.toggle_ignore } },
+  actions                = { ["ctrl-g"] = { actions.toggle_ignore } },
   winopts                = { preview = { winopts = { cursorline = false } } },
 }
 
@@ -266,8 +269,8 @@ M.defaults.git = {
     prompt   = "Commits> ",
     cmd      = "git log --color --pretty=format:'%C(yellow)%h%Creset "
         .. "%Cgreen(%><(12)%cr%><|(12))%Creset %s %C(blue)<%an>%Creset'",
-    preview  = "git show --pretty='%Cred%H%n%Cblue%an <%ae>%n%C(yellow)%cD%n%Cgreen%s'"
-        .. " --color {1}",
+    preview  = "git show --color {1}",
+    preview_pager = M._preview_pager_fn,
     actions  = {
       ["default"] = actions.git_checkout,
       ["ctrl-y"]  = { fn = actions.git_yank_commit, exec_silent = true },
@@ -277,8 +280,9 @@ M.defaults.git = {
   bcommits = {
     prompt   = "BCommits> ",
     cmd      = "git log --color --pretty=format:'%C(yellow)%h%Creset "
-        .. "%Cgreen(%><(12)%cr%><|(12))%Creset %s %C(blue)<%an>%Creset' <file>",
-    preview  = "git diff --color {1}^! -- <file>",
+        .. "%Cgreen(%><(12)%cr%><|(12))%Creset %s %C(blue)<%an>%Creset' {file}",
+    preview  = "git show --color {1} -- {file}",
+    preview_pager = M._preview_pager_fn,
     actions  = {
       ["default"] = actions.git_buf_edit,
       ["ctrl-s"]  = actions.git_buf_split,

lua/fzf-lua/previewer/builtin.lua

@@ -520,10 +520,10 @@ function Previewer.buffer_or_file:populate_terminal_cmd(tmpbuf, cmd, entry)
       end)
     end
   else
-    -- replace `<file>` placeholder with the filename
+    -- replace `{file}` placeholder with the filename
     local add_file = true
     for i, arg in ipairs(cmd) do
-      if arg == "<file>" then
+      if type(arg) == "string" and arg:match("[<{]file[}>]") then
         cmd[i] = entry.path
         add_file = false
       end

lua/fzf-lua/previewer/fzf.lua

@@ -250,6 +250,9 @@ function Previewer.git_diff:new(o, opts)
   self.cmd_modified = path.git_cwd(o.cmd_modified, opts)
   self.cmd_untracked = path.git_cwd(o.cmd_untracked, opts)
   self.pager = opts.preview_pager == nil and o.pager or opts.preview_pager
+  if type(self.pager) == "function" then
+    self.pager = self.pager()
+  end
   do
     -- populate the icon mappings
     local icons_overrides = o._fn_git_icons and o._fn_git_icons()
@@ -313,10 +316,14 @@ function Previewer.git_diff:cmdline(o)
     -- }
     -- we use ':format' directly on the user's command, see
     -- issue #392 for more info (limiting diff output width)
-    if not cmd:match("%%s") then
-      cmd = cmd .. " %s"
+    local fname_escaped = vim.fn.shellescape(file.path)
+    if cmd:match("[<{]file[}>]") then
+      cmd = cmd:gsub("[<{]file[}>]", fname_escaped)
+    elseif cmd:match("%%s") then
+      cmd:format(fname_escaped)
+    else
+      cmd = string.format("%s %s", cmd, fname_escaped)
     end
-    cmd = cmd:format(vim.fn.shellescape(file.path))
     cmd = ("LINES=%d;COLUMNS=%d;FZF_PREVIEW_LINES=%d;FZF_PREVIEW_COLUMNS=%d;%s %s")
         :format(fzf_lines, fzf_columns, fzf_lines, fzf_columns, cmd, pager)
     cmd = "sh -c " .. vim.fn.shellescape(cmd)

lua/fzf-lua/providers/git.lua

@@ -100,6 +100,9 @@ M.commits = function(opts)
   if not opts then return end
   if opts.preview then
     opts.preview = path.git_cwd(opts.preview, opts)
+    if type(opts.preview_pager) == "function" then
+      opts.preview_pager = opts.preview_pager()
+    end
     if opts.preview_pager then
       opts.preview = string.format("%s | %s", opts.preview, opts.preview_pager)
     end
@@ -132,14 +135,17 @@ M.bcommits = function(opts)
     local _, sel = utils.get_visual_selection()
     range = string.format("-L %d,%d:%s --no-patch", sel.start.line, sel["end"].line, file)
   end
-  if opts.cmd:match("<file") then
-    opts.cmd = opts.cmd:gsub("<file>", range or file)
+  if opts.cmd:match("[<{]file") then
+    opts.cmd = opts.cmd:gsub("[<{]file[}>]", range or file)
   else
     opts.cmd = opts.cmd .. " " .. (range or file)
   end
   if type(opts.preview) == "string" then
-    opts.preview = opts.preview:gsub("<file>", libuv.shellescape(file))
+    opts.preview = opts.preview:gsub("[<{]file[}>]", libuv.shellescape(file))
     opts.preview = path.git_cwd(opts.preview, opts)
+    if type(opts.preview_pager) == "function" then
+      opts.preview_pager = opts.preview_pager()
+    end
     if opts.preview_pager then
       opts.preview = string.format("%s | %s", opts.preview, opts.preview_pager)
     end