Rewrite library API

[MysteryBlokHed]

This PR is what I'll hopefully merge in the future instead of #142. It will completely rewrite the API for parsing & compiling to something that (hopefully) makes a bit more sense.

Instead of trying to slowly replace functions with new code like #142, I removed everything and started from scratch for most of the compilation API, bringing back old code as I needed it. Like #142, it changes the tokenization/parsing system to use the Pest library, then convert its tokens into an AST.

• [x] Rewrite parsing system to use Pest
• [x] Use tokens & ASTs instead of only tokens
• [x] Print custom errors for syntax problems instead of just printing Pest's
• [x] Get macros working
• [x] Get if statements working
• [x] Get while loops working
• [x] All tests passing
• [x] Update relevant documentation (after everything else)
• [x] Remove debug logs (after everything else)

[MysteryBlokHed]

A couple of tests are still failing, which I'll try to fix in the near future. After that, I'll still have to go through and do things like update docs, remove debug logs, etc.

[MysteryBlokHed]

I think this PR is just about ready. Assuming tests pass, I'll merge it in to main. It's nice to finally see this monolithic PR come to a close!

To future changes being much, much easier to implement!

[MysteryBlokHed]

The tests on macOS seem to be failing at random. On one of the runs, the test_no_config_out test failed. On a retry with nothing else changed, test_escape failed instead. I'm not sure what to do about that.

[MysteryBlokHed]

Merging anyway. Who's going to stop me