invalid escape sequence in documentation

[msyyc]

If docstring contains \, python will report warning:

related SDK issue: Azure/azure-sdk-for-python#35364

[msyyc]

I have checked that adding r for docstring could fix the issue: Azure/azure-sdk-for-python#35364 (comment)

[iscai-msft]

@msyyc the issue if we switch everything over to raw strings is that strings we have escaped before (with \) will no longer be escaped. Can you go through our autorest code and see where we are currently escaping strings?

[msyyc]

@iscai-msft I think it is reasonable for regex expression(e.g. \d) or windows path (e.g. C:\dev) in python class description. In such scenario, warning caused by python interpreter is fake warning and we shall avoid them. Currently autorest.python use """ by default in template (e.g. here), I think we could add logic that if docstring contains single slash \ then use r""" instead.

nit: I serach escape in autorest.python and find that current escape logic is not for docstring so the solution shall have no conflict