runtime(cs): Update C# runtime files

closes: #16884

Signed-off-by: Nick Jensen <nickspoon@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/ftplugin/cs.vim b/runtime/ftplugin/cs.vim
index ada7131..d40fe43 100644
--- a/runtime/ftplugin/cs.vim
+++ b/runtime/ftplugin/cs.vim
@@ -2,8 +2,7 @@
 " Language:            C#
 " Maintainer:          Nick Jensen <nickspoon@gmail.com>
 " Former Maintainer:   Johannes Zellner <johannes@zellner.org>
-" Last Change:         2022-11-16
-"                      2024 Jan 14 by Vim Project (browsefilter)
+" Last Change:         2025-03-14
 " License:             Vim (see :h license)
 " Repository:          https://github.com/nickspoons/vim-cs
 
@@ -21,8 +20,11 @@
 
 " Set 'comments' to format dashed lists in comments.
 setlocal comments=sO:*\ -,mO:*\ \ ,exO:*/,s1:/*,mb:*,ex:*/,:///,://
+setlocal commentstring=//\ %s
 
-let b:undo_ftplugin = 'setl com< fo<'
+setlocal cinoptions=J1
+
+let b:undo_ftplugin = 'setl com< fo< cino<'
 
 if exists('loaded_matchit') && !exists('b:match_words')
   " #if/#endif support included by default