bug#60972: 30.0.50; [PATCH]: Add html-ts-mode

[Eli Zaretskii]

> Cc: eliz@gnu.org
> From: Theodor Thornhill <theo@thornhill.no>
> Date: Fri, 20 Jan 2023 21:10:56 +0100
> 
> Attached is a ts-mode for HTML support.

Thanks.

> @Eli, is this ok for emacs-29, or should it go to master?  If ok for 29
> I'll remove the sentence/sexp-related stuff and commit that later on
> master.  Otherwise I'll just add everything to master.

Please install on master.

But please also add setting of auto-mode-alist, similarly to what we
do in other *-ts-mode's.  And a NEWS entry.