runtime(dockerfile): do not set commentstring in syntax script

fixes: #16268

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/ftplugin/dockerfile.vim b/runtime/ftplugin/dockerfile.vim
index 2e3c447..e45bf4c 100644
--- a/runtime/ftplugin/dockerfile.vim
+++ b/runtime/ftplugin/dockerfile.vim
@@ -1,7 +1,7 @@
 " Vim filetype plugin
 " Language:	Dockerfile
 " Maintainer:   Honza Pokorny <http://honza.ca>
-" Last Change:	2014 Aug 29
+" Last Change:	2024 Dec 20
 
 " Only do this when not done yet for this buffer
 if exists("b:did_ftplugin")
@@ -11,6 +11,6 @@
 " Don't load another plugin for this buffer
 let b:did_ftplugin = 1
 
-let b:undo_ftplugin = "setl commentstring<"
-
 setlocal commentstring=#\ %s
+
+let b:undo_ftplugin = "setl commentstring<"