Add ALT-ENTER to paste selected items into the buffer

- New fzf#vim#paste inserts selections instead of opening them
  - First item after cursor (space-padded), rest on following lines
  - Leading whitespace stripped only when pasting after text
- Commands opt in via `_paste`; key configurable with g:fzf_vim.paste_key
- Skip the key when buffer is not &modifiable
- Per command, paste:
  - path: Files, GFiles, GFiles?, Buffers, History, Locate
  - line text: Lines, BLines, Marks, Changes
  - matched text: Rg, Ag, Grep
  - tag name: Tags, BTags
  - commit hash: Commits, BCommits

doc/fzf-vim.txt

@@ -1,4 +1,4 @@
-fzf-vim.txt	fzf-vim	Last change: June 8 2025
+fzf-vim.txt	fzf-vim	Last change: May 31 2026
 FZF-VIM - TABLE OF CONTENTS                                *fzf-vim* *fzf-vim-toc*
 ==============================================================================
 
@@ -150,6 +150,11 @@ COMMANDS                                                      *fzf-vim-commands*
 
  - Most commands support CTRL-T / CTRL-X / CTRL-V key bindings to open in a new
    tab, a new split, or in a new vertical split
+ - Most commands support ALT-ENTER to insert the selected items into the
+   current buffer instead of opening them. The inserted text depends on the
+   command: file path (Files, GFiles, Buffers, History, Locate), line content
+   (Lines, BLines, Marks, Changes), matched text (Rg, Ag, Grep), tag name
+   (Tags, BTags), or commit hash (Commits, BCommits)
  - Bang-versions of the commands (e.g. `Ag!`) will open fzf in fullscreen
  - You can set `g:fzf_vim.command_prefix` to give the same prefix to the commands
    - e.g. `let g:fzf_vim.command_prefix = 'Fzf'` and you have `FzfFiles`, etc.
@@ -224,6 +229,18 @@ behavior with `g:fzf_vim.preview_window`. Here are some examples:
     "   let g:fzf_vim.preview_bash = 'C:\Git\bin\bash.exe'
 <
 
+Paste key~
+                                                            *fzf-vim-paste-key*
+                                                            *g:fzf_vim.paste_key*
+
+Most commands support a key to insert the selected items into the current
+buffer instead of opening them. Customize it with `g:fzf_vim.paste_key`.
+>
+    " Key to insert the selected items into the current buffer
+    " (default: 'alt-enter')
+    let g:fzf_vim.paste_key = 'alt-enter'
+<
+
 Command-level options~
                                                  *fzf-vim-command-level-options*