[Clang][NFC] Mark P2552 as implemented. (#92007)

wg21.link/P2552 suggest that __has_cpp_attribute
should return a non-zero value for all attributes that the
implementation does something interesting with.

Clang does something meaninful with all attributes except for:

- no_unique_address which we do not support for msvc target
- carries_dependency which arguably does nothing interesting. P2552
shies away from specifying a behavior for that attribute (despite being
the only one for which a recommandation would have been interesting,
arguably)

As such, we have nothing to change for this paper. This paper is a DR
and clang always behaved reasonably.