Sorry for the delay in review.
For the tests, include the lexer alias after a + (there are other examplefiles that do that as well). I only see the new lexer for .s files; please include a link if possible to the main project page, and merge to resolve conflicts.
Once you've done this, add a comment so I get notified, and I'll take another look.
Where should the lexer alias be added and which example files do that? I see two file names with a complete alias with a + but renaming my example files with the alias as extension does not seem to help → ``AssertionError: no lexer found for file 'ca65_example.ca65'``.