runtime(htmlangular): add html syntax highlighting

fixes: #15459
closes: #15552

Signed-off-by: Dennis van den Berg <dennis.vandenberg@nedap.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/syntax/htmlangular.vim

@@ -0,0 +1,18 @@
+" Vim syntax file
+" Language: Angular HTML template
+" Maintainer: Dennis van den Berg <dennis@vdberg.dev>
+" Last Change: 2024 Aug 22
+
+" quit when a syntax file was already loaded
+if exists("b:current_syntax")
+  finish
+endif
+
+if !exists("main_syntax")
+  let main_syntax = 'html'
+endif
+
+runtime! syntax/html.vim
+unlet b:current_syntax
+
+let b:current_syntax = "htmlangular"