R1:5a5c456264af

Correct docs of PhabricatorPHIDType::getAllTypesForApplication()

Summary: The signature and return type of the `getAllTypesForApplication()` function differed from its docs.

Test Plan: Carefully read the code of the function and compare it to the `getAllInstalledTypes()` function above from which the docs were incorrectly copied.

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno…