Code checker updates: Short array syntax and more

[james-cnz]

This contains several code checker updates:

• Short array syntax is now required
• Multi-line arrays should have trailing commas
• Return type mismatches
• The property renderer->numsections gives a warning in PHP 8.2, because it's not declared, and it appears no longer used

There's also an error for Moodle 4.3 with course/templates/completion_automatic.mustache now containing divs instead of spans, that I haven't addressed. I don't know if there's any way around this other than making a modified copy of the file.