[runtime] Improve highlighting in help files

[Franklin, Jason]

Greetings:

A number of section headings in help files are not highlighted properly.

For example...
1. :help undo_ftplugin
2. See FILE NAME (below) and FUNCTIONS (above) as examples

The syntax/help.vim file can be patched to fix this:

diff --git a/runtime/syntax/help.vim b/runtime/syntax/help.vim
index a8d45a4af..cd6f0b56c 100644
--- a/runtime/syntax/help.vim
+++ b/runtime/syntax/help.vim
@@ -11,7 +11,7 @@ endif
let s:cpo_save = &cpo
set cpo&vim

-syn match helpHeadline "^[-A-Z .][-A-Z0-9 .()_]*[ \t]\+\*"me=e-1
+syn match helpHeadline "^[-A-Z .][-A-Z0-9 .()_]*\ze\(\s\+\*\|$\)"
syn match helpSectionDelim "^===.*===$"
syn match helpSectionDelim "^---.*--$"
if has("conceal")

This problem can be seen all throughout the help files. This patch
improves the consistency of the help interface, IMHO.

--
Jason Franklin

[Bram Moolenaar]

Thanks. I'll include and try it out to check for any trouble.

--
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