Add window comparison plot to documentation

[thimotedupuch]

For the documentation I added a plot with the window functions as well as the frequency response, to give an overwiew of what's available.

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Thank you very much,
T.D.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.13%. Comparing base (77c99a2) to head (8d7af34).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #652   +/-   ##
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  Coverage   98.13%   98.13%           
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  Files          19       19           
  Lines        3279     3279           
=======================================
  Hits         3218     3218           
  Misses         61       61           

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[wheeheee]

Do you have a screenshot of that part of the docs?

[thimotedupuch]

It should look like this, with the sharp SVG image format and without the weird resizing effect this preview on github has

[wheeheee]

Oops, I actually meant what it looked like on the docs, whether it fits in or not. I built them and had a look.
So...I think the plot looks kind of awkward just floating above all those docstrings, but it's kinda useful so that's still acceptable, I guess...

[wheeheee]

Is it possible for you to make the window names on the left horizontal and in a slightly bigger font?
It would also be nice if you could add the script used to plot this.