Fix crash for non breaking spaces in docstring

[Pierre-Sassoulas]

This is a follow up of #2092. (Work in progress)

Closes #1762

[ichard26]

I'mma attach a skip news label under the impression that this PR finishes or fixes what was set out in PR GH-2092, which hasn't been released yet so a changelog entry isn't necessary.

edit: I also recommend marking this PR as a draft

[JelleZijlstra]

I feel like this should actually get a different news entry because it's about nbsps in docstrings, not comments.

[ichard26]

Ah, I was under the impression that PR GH-2092 had an unfixed bug which this PR fixes, now looking into it you are right @JelleZijlstra, thanks for letting me know!

[ichard26]

I was going through the issue tracker and found this issue: #1762, it seems to be what this PR aims to fix. If so, please link it so we don't have to remember to go close that issue when this is merged. Thank you in advance!

[Pierre-Sassoulas]

Funny, I opened this issue in October. I was thinking it might be the same problem. Thank you for digging it !

[ambv]

I added some more tests on this and found it to be fixed: eaa337f

Let's reopen if needed but it looks solved. Thanks for your contribution.

[Pierre-Sassoulas]

I just tested on the test I created, everything is working (no more crash for sure), thank you for fixing this so fast :)

Maybe a little something unrelated to the bug, with this input:

def function(a:int=42):
    """ This docstring start with a NBSP
        There is one NBSP column 5 here
       This is 7 NBSP
    """

    #    There's a NBSP + 3 spaces before
    #    And 4 spaces on the next line
    pass

Here's the diff compared to what I was expecting:

    def function(a: int = 42):
        """This docstring start with a NBSP
-     There is one NBSP column 5 here
+      There is one NBSP column 5 here
      This is 7 NBSP
      """
  
      #    There's a NBSP + 3 spaces before
      #    And 4 spaces on the next line
      pass

Probably because there is 7 spaces and not 8 on the last line of the docstring ? I'm going to close #1762 either way.