removed TODO

Author: changhoetyng

mypy/semanal.py

@@ -6461,8 +6461,6 @@ def lookup_fully_qualified_or_none(self, fullname: str) -> SymbolTableNode | Non
         Note that this can't be used for names nested in class namespaces.
         """
         # TODO: unify/clean-up/simplify lookup methods, see #4157.
-        # TODO: support nested classes (but consider performance impact,
-        #       we might keep the module level only lookup for thing like 'builtins.int').
         assert "." in fullname
         module, name = fullname.rsplit(".", maxsplit=1)
         if module not in self.modules: