Rename SpecialRecentchangeslinked class to SpecialRecentChangesLinked

For consistency with SpecialRecentChanges.

This introduces no incompatibilities as PHP classes are case-insensitive.

Change-Id: I5855074deed52fd7492f033c8a8fced8af647602
Merge "Rename SpecialRecentchangeslinked class to SpecialRecentChangesLinked"