* feat: allow identifiers in string concatenations

Resolves errors in strings of the form:

   ("failed in line %" PRIdLINENR)

---------

Co-authored-by: Lewis Russell <lewis6991@gmail.com>

This also lets it bind to _any_ statement, which is necessary for some
c++ attributes that can attach to the statement in if, while, and
do/while statements.

* Add support for C23 attributes

https://en.cppreference.com/w/c/language/attributes

* Use wrapper for statements with attributes to reduce state machine size

* Missed a couple _declarators that needed attributes directly after

* Use annotated_declarator for declarators that have attributes immediately following them

* Give field and type declarators the same attribute treatment

Fixes #32

Fixes #31

* Fix multi-statements in for initializer and update parts

* Finally the bug was only in the initializer part

Also, rewrite the way declarators are handled to produce a clearer AST