add alignas as an attribute type

[matter123]

This fixes the alignas issue reported at #121 (comment).

There should probably be a refactor of inline_attribute soonish to support, support attributes like PACKED or DLLEXPORT

[jeff-hykin]

Are spaces allowed in __declspec(? like __declspec (

[matter123]

Looks like yes https://godbolt.org/z/NqM5by

[jeff-hykin]

okay, then I think we should take it out of the representation, or we should make the representation a regex that matches it. I'll try to find the best way to incorporate that for the other similar things too.

I think it might be best to remove the ()'s from the representation, and then just have the function-like adjective to indicate that it needs ()'s in the pattern

[matter123]

Ok, the concern is with __attribute__(( as it has double parenthesis on both sides. e.g. __attribute__((noreturn)) or __attribute((constructor(101)))

Edit: __attribute__ and __attribute allow spaces between them and (( as well.

[jeff-hykin]

I went ahead an manually merged this in just now. I moved them out of tokens though so that we can change them to include spaces in the future.