Deprecate sphinx.util.typing.unicode and remove all usage

[jdufresne]

The definition is unnecessary.

[codecov]

Codecov Report

Merging #5745 into master will increase coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #5745      +/-   ##
==========================================
+ Coverage   83.23%   83.24%   +<.01%     
==========================================
  Files         296      296              
  Lines       39625    39621       -4     
  Branches     5881     5880       -1     
==========================================
  Hits        32982    32982              
+ Misses       5279     5275       -4     
  Partials     1364     1364

Impacted Files	Coverage Δ
sphinx/versioning.py	82.24% <ø> (ø)	⬆️
sphinx/ext/mathbase.py	48.57% <ø> (ø)	⬆️
sphinx/writers/html.py	88.67% <ø> (ø)	⬆️
sphinx/domains/changeset.py	88.88% <ø> (ø)	⬆️
sphinx/builders/latex/__init__.py	78.26% <ø> (ø)	⬆️
sphinx/config.py	82.74% <ø> (ø)	⬆️
sphinx/ext/inheritance_diagram.py	37.66% <ø> (ø)	⬆️
sphinx/locale/__init__.py	76.76% <ø> (ø)	⬆️
sphinx/util/inventory.py	92.72% <ø> (ø)	⬆️
sphinx/util/__init__.py	67.28% <ø> (ø)	⬆️
... and 143 more

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[tk0miya]

Sorry, I'm using this now for migration to mypy-py3 mode. So please keep this as is for a while.

Note: this is added only in master branch. So deprecation is not needed because it is not released yet.

[jdufresne]

Instead of using the alias, wouldn't it make more sense to change the uses of unicode to str? What is the rationale? Or is that considered "step 2" in the process?

[tk0miya]

Yes, I'll replace all unicode types after migration to mypy-py3 mode. I hope this alias makes the "diff" of the migration pull request small and review-able.

[tk0miya]

Yes, I'll replace all unicode types after migration to mypy-py3 mode.

Now I'm working for mypy-py3 mode in #5760. And I'll merge it after a while (if no objection). After that, I'll replace all of unicode type with str type.

[tk0miya]

I replaced all "unicode" type by "str" in #5773.
Thanks,