feat: allow bufnr optional parameter for get_current_dir function

This allows for using get_current_dir in cases where currently hovered
buffer is not the desired Oil buffer (e.g. displaying directories for
multiple different Oil buffers)

doc/api.md

@@ -83,11 +83,15 @@ Change how oil determines if the file is hidden
 Toggle hidden files and directories
 
 
-## get_current_dir()
+## get_current_dir(bufnr)
 
-`get_current_dir(): nil|string` \
+`get_current_dir(bufnr): nil|string` \
 Get the current directory
 
+| Param | Type           | Desc                                          |
+| ----- | -------------- | --------------------------------------------- |
+| bufnr | `nil\|integer` | When nil, get directory of the current buffer |
+
 
 ## open_float(dir)
 

doc/oil.txt

@@ -277,9 +277,11 @@ toggle_hidden()                                                *oil.toggle_hidde
     Toggle hidden files and directories
 
 
-get_current_dir(): nil|string                                *oil.get_current_dir*
+get_current_dir({bufnr}): nil|string                         *oil.get_current_dir*
     Get the current directory
 
+    Parameters:
+      {bufnr} `integer` When nil, get directory of the current buffer
 
 open_float({dir})                                                 *oil.open_float*
     Open oil browser in a floating window

lua/oil/init.lua

@@ -140,12 +140,14 @@ M.toggle_hidden = function()
 end
 
 ---Get the current directory
+---@param bufnr? integer
 ---@return nil|string
-M.get_current_dir = function()
+M.get_current_dir = function(bufnr)
   local config = require("oil.config")
   local fs = require("oil.fs")
   local util = require("oil.util")
-  local scheme, path = util.parse_url(vim.api.nvim_buf_get_name(0))
+  local buf_name = vim.api.nvim_buf_get_name(bufnr or 0)
+  local scheme, path = util.parse_url(buf_name)
   if config.adapters[scheme] == "files" then
     assert(path)
     return fs.posix_to_os_path(path)