help_ja.vim: support small caption ja specific rule

Author: tsuyoshicho

syntax/help_ja.vim

@@ -8,3 +8,8 @@ syn region helpTransNote start="{訳注:" end="}" contains=helpLeadBlank,helpHyp
 syn region helpBracesInTransNote start=".{"ms=e end="}."me=s transparent contained contains=helpLeadBlank,helpHyperTextJump,helpBracesInTransNote
 syn match helpSpecial "[。、]\zs\[[-a-z^A-Z0-9_]\{2,}]"
 hi def link helpTransNote Special
+if has("conceal")
+  syn region helpHeadline matchgroup=helpIgnore start="^☆\(\s\)\@!" end="\ze\(\s\+\*\|$\)" keepend concealends
+else
+  syn region helpHeadline matchgroup=helpIgnore start="^☆\(\s\)\@!" end="\ze\(\s\+\*\|$\)" keepend
+endif