._update_indent() was changed not to take arguments and IPython.core.usage.quick_guide was removed.

In test_execute_async_returns_failure_on_runtime_error_and_captures_expected_stack the comment was causing an IndentationError, changing it to a docstring fixes the problem. I don't think this is related to IPython but probably a python 3.6 problem.

Refs #21251

The IPython InputSplitter is assuming an interactive front end whereas
we have the whole code at once and do not have to anticipate users
possibly entering more. The new InputSplitter overrides
behaviour of IPython InputSplitter for these cases.
Refs #21251