Support more C integer literal suffix syntaxes

[JosephPecoraro]

https://en.cppreference.com/w/cpp/language/integer_literal

• Allow for z for size_t with C++23 / C++2b.
• Allow for the u to be either before or after the l, ll, or z.
• Allow for intermixing case everywhere except for the ll or LL unit.

Before:

After:

[JosephPecoraro]

@sorbits Hoping this is an easy change to review!