Description Of The Issue

In the docs app, overload signatures are shown for methods on Observable - e.g. five overload signatures are shown for subscribe.

However, overload signatures are not shown for operators. That makes documenting shareReplay somewhat difficult, as it has a number of signatures - including a signature that takes a single config object. The same problem exists for the config object signature added for retry in this PR.

It's not clear what needs to be done to effect the showing of overload signatures for operators and I'm not sure what it is that effects them for Observable#subscribe - as there doesn't seem to be anything specific to overloads in the TSDoc.