patch 9.1.0464: no whitespace padding in commentstring option in ftplugins

Problem:  no whitespace padding in commentstring option in ftplugins
Solution: Change default to include whitespace padding, update
          existing filetype plugins with the new default value
          (Riley Bruins)

closes: #14843

Signed-off-by: Riley Bruins <ribru17@hotmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/ftplugin/pdf.vim b/runtime/ftplugin/pdf.vim
index 1ed9911..96c77c8 100644
--- a/runtime/ftplugin/pdf.vim
+++ b/runtime/ftplugin/pdf.vim
@@ -2,13 +2,14 @@
 " Language:	PDF
 " Maintainer:	Tim Pope <vimNOSPAM@tpope.info>
 " Last Change:	2007 Dec 16
+" 		2024 May 23 by Riley Bruins <ribru17@gmail.com> ('commentstring')
 
 if exists("b:did_ftplugin")
     finish
 endif
 let b:did_ftplugin = 1
 
-setlocal commentstring=%%s
+setlocal commentstring=%\ %s
 setlocal comments=:%
 let b:undo_ftplugin = "setlocal cms< com< | unlet! b:match_words"