Ignore this runtime-only import

I've queried this in https://github.com/python/typeshed/issues/4360,
though I suspect the answer is going to be to have an ignore comment
like this.

jedi/utils.py

@@ -2,7 +2,7 @@
 Utilities for end-users.
 """
 
-import __main__
+import __main__  # type: ignore[import]
 from collections import namedtuple
 import logging
 import traceback