Update runtime files.
diff --git a/runtime/ftplugin/vim.vim b/runtime/ftplugin/vim.vim
index b87e144..3307de5 100644
--- a/runtime/ftplugin/vim.vim
+++ b/runtime/ftplugin/vim.vim
@@ -1,7 +1,7 @@
" Vim filetype plugin
" Language: Vim
" Maintainer: Bram Moolenaar <Bram@vim.org>
-" Last Change: 2020 Aug 14
+" Last Change: 2021 Jan 05
" Only do this when not done yet for this buffer
if exists("b:did_ftplugin")
@@ -48,18 +48,23 @@
" Use :help to lookup the keyword under the cursor with K.
setlocal keywordprg=:help
-" Set 'comments' to format dashed lists in comments
-" Avoid that #{} starts a comment.
-setlocal com=sO:\"\ -,mO:\"\ \ ,sO:#\ -,mO:#\ \ ,eO:##,:\",b:#
+if "\n" .. getline(1, 10)->join("\n") =~# '\n\s*vim9\%[script]\>'
+ " Set 'comments' to format dashed lists in comments
+ setlocal com=sO:#\ -,mO:#\ \ ,eO:##,:#
+ " Comments start with a double quote in a legacy script;
+ " with # in a Vim9 script
+ setlocal commentstring=\"%s
+else
+ setlocal com=sO:\"\ -,mO:\"\ \ ,:\"
+ setlocal commentstring=#%s
+endif
+
" Format comments to be up to 78 characters long
if &tw == 0
setlocal tw=78
endif
-" Comments start with a double quote; in Vim9 script # would also work
-setlocal commentstring=\"%s
-
if !exists("no_plugin_maps") && !exists("no_vim_maps")
let b:did_add_maps = 1