Add some more common abbreviations to the rule keyword command list

[Anonymous4045]

I believe it would be beneficial to add two more shorthands for invoking the 'Rules' embed: "hw" and "eng". "hw" is a common shorthand for "homework", so it should be associated with the embed for rule 8. Likewise, "eng" is a common abbreviation for "English", so it can be linked with rule 4.

[wookie184]

The rule abbreviations are stored here

site/pydis_site/apps/api/views.py

Line 133 in 3ee7d07

return Response([

, so i'll move this to the site repo.

As for adding them, I don't really have an opinion either way, but it sounds fine.