Mypy 1.5 additional checks (#746)

.mypy.ini

@@ -10,12 +10,15 @@ disallow_subclassing_any = True
 disallow_untyped_calls = True
 disallow_untyped_decorators = True
 disallow_untyped_defs = True
+# TODO(PY312): explicit-override
 enable_error_code = ignore-without-code, possibly-undefined, redundant-expr, redundant-self, truthy-bool, truthy-iterable, unused-awaitable
+extra_checks = True
 implicit_reexport = False
 no_implicit_optional = True
 pretty = True
 show_column_numbers = True
 show_error_codes = True
+show_error_code_links = True
 strict_equality = True
 warn_incomplete_stub = True
 warn_redundant_casts = True