patch 9.1.1359: filetype: GNU Radio config files are not recognized

Problem:  filetype: GNU Radio config files are not recognized.
Solution: detect GNU Radio config files as confini filetype.  Only
          allow '#' as start of comment in confini syntax (zeertzjq).

Ref:
- https://wiki.gnuradio.org/index.php/Configuration_Files

closes: #17242

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/syntax/cfg.vim

@@ -1,7 +1,7 @@
 " Vim syntax file
 " Language:	Good old CFG files
 " Maintainer:	Igor N. Prischepoff (igor@tyumbit.ru, pri_igor@mail.ru)
-" Last change:	2012 Aug 11
+" Last Change:	2012 Aug 11
 " 2024 Nov 14 by Vim project:  // only denotes a comment when starting a line (#16051)
 
 " quit when a syntax file was already loaded

runtime/syntax/confini.vim

@@ -1,5 +1,7 @@
 " Vim syntax file
 " Language: confini
+" Last Change:
+" 2025 May 02 by Vim project commented line starts with # only
 
 " Quit if a syntax file was already loaded
 if exists("b:current_syntax")
@@ -9,4 +11,8 @@ endif
 " Use the cfg syntax for now, it's similar.
 runtime! syntax/cfg.vim
 
+" Only accept '#' as the start of a comment.
+syn clear CfgComment
+syn match CfgComment "#.*" contains=@Spell
+
 let b:current_syntax = 'confini'