Summary

This PR removes the todo!() around IpyEscapeCommand in the formatter.

The NeedsParentheses trait needs to be implemented which always return Never. The reason being that if an escape command is parenthesized, then that's not parsed as an escape command. IOW, the parentheses shouldn't be present around an escape command.

In the similar way, the CanSkipOptionalParenthesesVisitor will skip this node.

Test Plan

Updated the unformatted.ipynb fixture with new cells containing IPython escape commands and the corresponding snapshot was verified. Also, tested it out in a few open source repositories containing notebooks (openai/openai-cookbook, huggingface/notebooks).

New cells in unformatted.ipynb

Cell 2

A markdown cell

Cell 3

def some_function(foo, bar):
    pass
%matplotlib inline

Cell 4

foo = %pwd
def some_function(foo,bar,):
	foo = %pwd
    print(foo
	)

fixes: #8204