Fix symbol list matching regexp performance
Allow empty face lists, improve the face list matching regexp (see
discussion in Bug#69714) based on relint's comments, add tests:
* test/lisp/emacs-lisp/ert-font-lock-tests.el: Add tests.
* lisp/emacs-lisp/ert-font-lock.el: Fix regexps.
Fail on files with no assertions, parser now accepts multiple
carets per line and face lists:
* lisp/emacs-lisp/ert-font-lock.el: Assertion parser fix.
* test/lisp/emacs-lisp/ert-font-lock-resources/no-asserts.js:
* test/lisp/emacs-lisp/ert-font-lock-tests.el
(test-parse-comments--no-assertion-error)
(test-syntax-highlight-inline--caret-negated-wrong-face)
(test-macro-test--file-no-asserts): New test cases.
* doc/misc/ert.texi (Syntax Highlighting Tests): More syntax examples.
Add ert-font-lock as well as unit tests and testing resources.
* lisp/emacs-lisp/ert-font-lock.el: New library.
* test/lisp/emacs-lisp/ert-font-lock-resources/broken.js:
* test/lisp/emacs-lisp/ert-font-lock-resources/correct.js:
* test/lisp/emacs-lisp/ert-font-lock-tests.el: Unit tests.
(Bug#67460)
