bug#46416: 27.1; syntax-propertize fails in mhtml-mode

[Dmitry Gutov <dgutov@yandex.ru>]

On 10.02.2021 03:40, Leo Liu wrote:
> 1. emacs -q -l test.el
> 2. Create a new buffer in mhtml-mode
> 3. Add the following two lines:
> 
>     %%var1%%
>     "%%var2%%"
> 
> 4. Inspect the syntax of the % char (C-u C-x =) on both lines
> 
> % in double quotes has word syntax which seems unexpected.
> 
> If we do something similar in Emacs 26 both % chars have punctuation
> syntax.

I can't seem to be able to reproduce your scenario in Emacs 28 (in fact, 
I get %var1 and %var2 highlighted as variables), but it might be related 
to the

   "\\([\"']\\)[^\"'<>]*"

rule in sgml-syntax-propertize-rules.

If you could double-check the expected and actual behaviors in the 
current master, though, that would be great.