handle overrides in reference searching

[shellderp]

3 scenarios:

• TargetClass has a method TargetMethod which a subclass SubClass does not override, in this case show all references to TargetMethod invoked on SubClass
• TargetClass has a method TargetMethod which a subclass SubClass overrides, in this case do not show references to TargetMethod invoked on SubClass
• TargetClass has a method TargetMethod which is an overriden method from BaseClass; in this case, try to determine if a reference to TargetClass::TargetMethod == Baseclass::TargetMethod