Annotate every indirect sugar-method

Annotate every indirect sugar-method

Now that the churn is over we can add annotations to each method a user ought
to never override. See next commit for the actual use case and diagnostics
emitter.

Unfortunately this adds yet another small compile-time hit, similar to
73f54e27 (a hit incurred regardless whether the upcoming validation framework
is used or not). Complete test of DBIx::Class::Helpers v2.032002 goes from
about ~64.6 seconds CPU time up to ~65.5, adding another ~1% of startup speed
loss. The savings in debugging sessions should make this all worth it... or
so one hopes.