Report inconsistent lifetime registrations in conventions

[kzu]

A given type may match more than once when using convention registrations (i.e. typeof(IDisposable) and separately, by regex).

Ideally there should be no overlap for the same concrete type, as that may cause weird lifetime bugs due to the first one to register the implementation type to "win" (since we use TryAddXXX). So it should be a warning to have a case where this happens.