PEP 484: Fix citation references

[hugovk]

Fix some Sphinx build warnings.

(for readability, paths trimmed in warnings shown here)

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pep-0484.txt:2490: WARNING: Citation [peps] is not referenced.

This was a misplaced underscore, now fixed.

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pep-0484.txt:2463: WARNING: duplicate citation mypy, other instance in pep-0482.txt

The exact same citation is already defined in pep-482.txt, Sphinx uses that one.

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pep-0484.txt:2475: WARNING: duplicate citation pyflakes, other instance in pep-0482.txt
pep-0484.txt:2478: WARNING: duplicate citation pylint, other instance in pep-0482.txt

These aren't actually used in this file, we can delete them.

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Also remove the redundant emacs metadata from the end of the file.

[AA-Turner]

The exact same citation is already defined in pep-482.txt, Sphinx uses that one.

I think it would be good to have each PEP be standalone -- should PEP 482 ever change, we might inadvertently introduce build errors on this PEP.

Probably better to turn it into an inline link here, as the rendering is already odd as the markup is a reST citation rather than a reST footnote (which must either begin with # or be numeric):

A

[AA-Turner]

Actually, all the citations in PEP-484 have no content beyond links -- I'd support inlining them all, especially as it is a reasonably well referenced document.

A

[hugovk]

Updated!

[AA-Turner]

Line 49 needs to be similarly updated (can't add a review comment)

A

[hugovk]

Thanks, done!