Only show first overload in a series of consecutive overload signatures

...for navigateTo.

Current semantics:
* If an overload lacks an implementation, go to the first overload.
* If an overload has any implementation, go to the first one.
* If there are any declarations between an implementation and any overload, this will split the series of overloads (note that this is invalid code).
I think this is explained decently by the preceding comment about constructor parameters.