chore: Remove allowed_strings in favour of Literal

[doublevcodes]

This PR removes the allowed_strings converter because we can use typing.Literal as a converter to the same effect

[jchristgit]

Great change, thank you!

Once the review by Tizzy is dealt with, this looks good to merge.

[MarkKoz]

I don't think Literal does a conversion to lowercase, but I don't think anyone was relying on that feature previously.

[onerandomusername]

Looks good, just need the noqa removal.

[ichard26]

Hey @doublevcodes, it's been a while, do you plan on resuming work on this PR or should we put this up for grabs? Thank you!

[doublevcodes]

Hey @doublevcodes, it's been a while, do you plan on resuming work on this PR or should we put this up for grabs? Thank you!

Hey, sorry for the delay, I can finish this in the coming week.

[doublevcodes]

I fixed the noqas, but I did something and now I have 64 changed files 😅

[Bluenix2]

Use git reset to remove that commit, then rebase your old commit off of upstream/main and force push?

[Xithrius]

@doublevcodes are you still planning on fixing up the conflicts in this PR?

[MarkKoz]

I'm going to finish this up since there has not been a response for over a week. Seems almost done anyway.

[MarkKoz]

Unfortunately I used the wrong command and ended up pushing my local main branch to doublevcodes/main, causing the diff to disappear and the PR to close. I can't push to that remote anymore since the PR is closed, and I have no way to reopen the PR. So I will have to just create a new PR unfortunately.