DOC: E252 is not documented

[wjandrea]

https://pycodestyle.pycqa.org/en/latest/intro.html#error-codes

E251 unexpected spaces around keyword / parameter equals

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E261 at least two spaces before inline comment

It should say:

E251 unexpected spaces around keyword / parameter equals

E252 missing whitespace around parameter equals

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E261 at least two spaces before inline comment

E252 was added in #717, per change log for 2.4.0 (2018-04-10).