Updated UnusedVariables for the new AST.

Signed-off-by: Yorick Peterse <yorickpeterse@gmail.com>
Cleanup for MethodValidation.

With this cleanup comes the renaming of "definition_type" to "method_type"
since this particular attribute doesn't make much sense out of the context of
defining methods.

Signed-off-by: Yorick Peterse <yorickpeterse@gmail.com>