Find usages does not find usage of constructors

When clicking "find usages" on a constructor, Creator finds all the places where the class name is mentioned, i.e. in all "Class::" prefixes for scope resolution (all the methods in the .cpp file, and so on).

It should instead just find where that particular constructor (in case of overloads) is being used. The previous behaviour could be kept when someone does "Find usages" on the class name in the declaration.