ert-font-lock patch (bug#67460)

[Vladimir Kazanov]

Hi all,

Could somebody please look into the patch I provided some time ago for Emacs?

The patch adds an ert extension, ert-font-lock, that makes it very
easy to check faces set by font lock, and is based on tree-sitters
syntax highlighting unit test syntax - aiming to simplify porting of
the tree-sitter grammar tests to Emacs.

Originally it was suggested for ELPA but Eli and team pointed out that
it would be convenient to use alongside ert in Emacs. After removing
cl-lib dependency and fixing other issues, I've prepared a patch for
master (see [1].

I've tested the system in my (relatively obscure) quakec-mode and
quakec-ts-mode major modes. It was also used to test lua-ts-mode with
some positive feedback by the author of the mode.

[1] https://lists.gnu.org/archive/html/bug-gnu-emacs/2023-11/msg01507.html
- the patch submission
[2] https://lists.gnu.org/archive/html/emacs-devel/2023-11/msg00867.html
- the original ELPA submission discussion

The plan is to also prepare a package for ELPA for reverse
compatibility purposes. If there's no interest in including
ert-font-lock in Emacs, I can always fall back to this option.

Thanks a lot

--
Regards,

Vladimir Kazanov