feat(git): support detached working trees (#2597)

* feat(git): support detached working trees

closes #2595

* [docgen] Update doc/telescope.txt
skip-checks: true

* fix: use_file_path

---------

Co-authored-by: Github Actions <actions@github>

lua/telescope/utils.lua

@@ -517,4 +517,22 @@ utils.__warn_no_selection = function(name)
   })
 end
 
+--- Generate git command optionally with git env variables
+---@param args string[]
+---@param opts? table
+---@return string[]
+utils.__git_command = function(args, opts)
+  opts = opts or {}
+
+  local _args = { "git" }
+  if opts.gitdir then
+    vim.list_extend(_args, { "--git-dir", opts.gitdir })
+  end
+  if opts.toplevel then
+    vim.list_extend(_args, { "--work-tree", opts.toplevel })
+  end
+
+  return vim.list_extend(_args, args)
+end
+
 return utils