phases: change the way we warm the phasecache in repocache Same logic as for the previous chngeset. We are about to rename and change the method used here.

phases: use a more generic way to trigger a phases computation for perf Querying the tip most revision will require the cache to warm the same as calling the dedicated method. This avoid using a method that is mostly meant for internal use and will be renamed in a coming changesets.

phases: fix an overzealous invalidation of the phase sets If `len(cl) == self._loadedrevslen` the cache is up to date.

phases: type annotation for `_phasesets` Does not hurt.