Adapt to a vim pkg rename/replacement in Nixpkgs

Addresses an error like the following:
```sh-session
$ sudo darwin-rebuild --verbose --print-build-logs switch
building the system configuration...
fetching git input 'git+file:///private/etc/nix-darwin'
error:
       … while evaluating an expression to select 'drvPath' on it
         at «internal»:1:552:
       … while evaluating strict
         at «internal»:1:552:
       (stack trace truncated; use '--show-trace' to show the full trace)

       error: 'vim_configurable' has been renamed to/replaced by 'vim-full'
```

See <NixOS/nixpkgs@853d9f3>

Fixes nix-darwin#1622

Author: Josh-Tilles

modules/programs/vim.nix

@@ -77,7 +77,7 @@ in
   config = mkIf cfg.enable {
 
     environment.systemPackages =
-      [ # Include vim_configurable package.
+      [ # Include vim-full package.
         cfg.package
       ];
 
@@ -92,7 +92,7 @@ in
       endif
     '';
 
-    programs.vim.package = pkgs.vim_configurable.customize {
+    programs.vim.package = pkgs.vim-full.customize {
       name = "vim";
       vimrcConfig.customRC = config.environment.etc."vimrc".text;
       vimrcConfig.vam = {