[C] Update keywords-parens for alignof and static_assert

[braewoods]

I overlooked this previously but I believe this is an optimization for sizeof that would also apply these two that I previously added.

[deathaxe]

Small tests would probably avoid regressing that change by future changes.

[braewoods]

What would you suggest then? I already added tests for these previously.

[deathaxe]

Obviously not for parenthesed variants, I guess. Otherwise they would have been failing due this commit missing.

It turns out the keywords-parens to be redundant, because both keywords (e.g. sizeof and parentheses aka. groups are already matched by other patterns.

[braewoods]

It turns out the keywords-parens to be redundant, because both keywords (e.g. sizeof and parentheses aka. groups are already matched by other patterns.

Should they be removed then?

[deathaxe]

There are more such constructs. Not familiar enough with the syntax definition's architecture to say that for sure. Maybe safer to keep them until a rewrite.