runtime(dosini): Add support for # comments to ftplugin

runtime/syntax/dosini.vim supports both ; and # as comments, and I think
a bunch of the files detected as dosini do too, so add support for # to
the ftplugin.

closes: #16681

Signed-off-by: David Mandelberg <david@mandelberg.org>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/ftplugin/dosini.vim b/runtime/ftplugin/dosini.vim
index 6a53dfd..3470bd3 100644
--- a/runtime/ftplugin/dosini.vim
+++ b/runtime/ftplugin/dosini.vim
@@ -1,7 +1,8 @@
 " Vim filetype plugin file
 " Language:             Configuration File (ini file) for MS-DOS/MS Windows
+" Maintainer:           This runtime file is looking for a new maintainer.
 " Previous Maintainer:  Nikolai Weibull <now@bitwi.se>
-" Latest Revision:      2008-07-09
+" Latest Revision:      2025 Feb 20
 
 if exists("b:did_ftplugin")
   finish
@@ -13,7 +14,7 @@
 
 let b:undo_ftplugin = "setl com< cms< fo<"
 
-setlocal comments=:; commentstring=;\ %s formatoptions-=t formatoptions+=croql
+setlocal comments=:;,:# commentstring=;\ %s formatoptions-=t formatoptions+=croql
 
 let &cpo = s:cpo_save
 unlet s:cpo_save