Add Clash numeric types plus basic impls

[rslawson]

This implements basic functionality for Index<N, T>, Unsigned<N, T>, Signed<N, T>, and BitVec<N, M>. This PR is currently marked as draft since I still need to:

• Add documentation to the types themselves and to the size check traits, not just their methods
• Create macros as aliases for the types
• Create instantiation macros
• Add tests?

Anywho, at least an initial review pass and/or suggestions on things I should add in this PR that I didn't (and that I don't have WIP stuff for already from before I did a lot of downscoping, like operator impls).

[hydrolarus]

Have you done any tests to see if generated code does not need any trait bounds? To me it seems like it it shouldn't be required, but there's no usage examples, just making sure since I'm afraid of trait bounds 😱

[rslawson]

Have you done any tests to see if generated code does not need any trait bounds? To me it seems like it it shouldn't be required, but there's no usage examples, just making sure since I'm afraid of trait bounds 😱

I haven't done that yet, no. That's what I'll be working on today, so hopefully it's something I can complete today (^:

[hydrolarus]

Wouldn't it make sense to also support binary literals and maybe even base 10 literals?

[rslawson]

I could add support for binary literals pretty easily, just the issue is that for decimal literals there's the issue of not having a way to turn that into binary very easily past a certain size.

[hydrolarus]

I've been thinking if there is a good way to use from_str_radix for this instead of hand rolling this, but I guess you want arbitrarily large literals too, so this wouldn't work 😔 Maybe this could be a comment here though? Otherwise I'll wonder the same thing in two months when I look at this again haha

[hydrolarus]

This could check for the first element to have less manual shuffling of the characters in the string

Suggested change

	array_str.push('[');
	for byte in buf {
	write!(array_str, "0x{byte:02x}, ").unwrap();
	}
	array_str.pop();
	array_str.pop();
	array_str.push(']');
	array_str.push('[');
	for (i, byte) in buf.iter().enumerate() {
	if i > 0 {
	write!(array_str, ", ").unwrap();
	}
	write!(array_str, "0x{byte:02x}").unwrap();
	}
	array_str.push(']');

[rslawson]

Marked as ready for review. I know there's one more thing I need to do (sign extension for Signed<N, T> when converting from BitVector<M, N>) before it's actually ready to go, but what with all the other things I want to do done plus all the tests passing I'm happy to call it ready for review.