When -Woverloaded-virtual is triggered, call HandleFunctionTypeMismatch to add
more information to the notes.  This information is already present on other
diagnostic messages that involves overloads.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178923 91177308-0d34-0410-b5e6-96231b3b80d8