MAINT: fix typing mypy 1.0 (#13933)

IPython/core/guarded_eval.py

@@ -609,8 +609,8 b' SUPPORTED_EXTERNAL_GETITEM = {'
 
 BUILTIN_GETITEM: Set[InstancesHaveGetItem] = {
     dict,
-    str,
-    bytes,
+    str,  # type: ignore[arg-type]
+    bytes,  # type: ignore[arg-type]
     list,
     tuple,
     collections.defaultdict,
@@ -619,7 +619,7 b' BUILTIN_GETITEM: Set[InstancesHaveGetItem] = {'
     collections.ChainMap,
     collections.UserDict,
     collections.UserList,
-    collections.UserString,
+    collections.UserString,  # type: ignore[arg-type]
     _DummyNamedTuple,
     _IdentitySubscript,
 }