runtime(gdshader): add comments and commentstring to ftplugin

closes: #17500

Co-authored-by: Riley Bruins <ribru17@hotmail.com>
Signed-off-by: Maxim Kim <habamax@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/ftplugin/gdshader.vim b/runtime/ftplugin/gdshader.vim
index 809a005..a66c6cf 100644
--- a/runtime/ftplugin/gdshader.vim
+++ b/runtime/ftplugin/gdshader.vim
@@ -4,10 +4,13 @@
 # Language: Godot shading language
 # Maintainer: Maxim Kim <habamax@gmail.com>
 # Website: https://github.com/habamax/vim-gdscript
+# Last Update: 2025-06-09
 
 if exists("b:did_ftplugin") | finish | endif
 b:did_ftplugin = 1
 
-b:undo_ftplugin = 'setlocal suffixesadd<'
+b:undo_ftplugin = 'setlocal suffixesadd< comments< commentstring<'
 
 setlocal suffixesadd=.gdshader
+setlocal comments=sO:*\ -,mO:*\ \ ,exO:*/,s1:/*,mb:*,ex:*/,://
+setlocal commentstring=//\ %s