runtime(vim): vimHLGroup is not highlighted correctly

Problem: vimHLGroup is not highlighted in "hi def link"
          and "hi clear" commands
Solution: highlight vimHLGroup similarly to vimGroup
          (Eisuke Kawashima)

closes: #17450

Signed-off-by: Eisuke Kawashima <e-kwsm@users.noreply.github.com>
Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/syntax/vim.vim b/runtime/syntax/vim.vim
index 3eafe1e..2d7493a 100644
--- a/runtime/syntax/vim.vim
+++ b/runtime/syntax/vim.vim
@@ -1622,7 +1622,7 @@
 syn match	vimHiGuiRgb	contained	"#\x\{6}"
 
 " Highlighting: hi group key=arg ... {{{2
-syn cluster	vimHiCluster contains=vimGroup,vimHiGroup,vimHiNone,vimHiTerm,vimHiCTerm,vimHiStartStop,vimHiCtermFgBg,vimHiCtermul,vimHiCtermfont,vimHiGui,vimHiGuiFont,vimHiGuiFgBg,vimHiKeyError,vimNotation,vimComment,vim9comment
+syn cluster	vimHiCluster contains=vimGroup,vimHLGroup,vimHiGroup,vimHiNone,vimHiTerm,vimHiCTerm,vimHiStartStop,vimHiCtermFgBg,vimHiCtermul,vimHiCtermfont,vimHiGui,vimHiGuiFont,vimHiGuiFgBg,vimHiKeyError,vimNotation,vimComment,vim9comment
 syn region	vimHiKeyList	contained 	start="\i\+" skip=+\\\\\|\\|\|\n\s*\\\|\n\s*"\\ + matchgroup=vimCmdSep end="|" excludenl end="$" contains=@vimContinue,@vimHiCluster
 if !exists("g:vimsyn_noerror") && !exists("g:vimsyn_vimhikeyerror")
  syn match	vimHiKeyError	contained	"\i\+="he=e-1
@@ -1640,7 +1640,7 @@
 syn match	vimHiNmbr	contained	'\d\+'
 
 " Highlight: clear {{{2
-syn keyword	vimHiClear	contained	clear	skipwhite nextgroup=vimGroup,vimHiGroup
+syn keyword	vimHiClear	contained	clear	skipwhite nextgroup=vimGroup,vimHLGroup,vimHiGroup
 
 " Highlight: link {{{2
 " see tst24 (hi def vs hi) (Jul 06, 2018)