change format_args to prefer annotations from typing.get_type_hints

[terencehonles]

Subject: change format_args to prefer annotations from typing.get_type_hints

Feature or Bugfix

• Bugfix

Purpose

The current code looks for the pattern:

class Node:
    def parent(self) -> 'Node': pass

This change allows more complex forward references:

class Node:
    def children(self) -> Set['Node']: pass

[codecov]

Codecov Report

Merging #5280 into master will decrease coverage by 0.8%.
The diff coverage is 11.11%.

@@            Coverage Diff             @@
##           master    #5280      +/-   ##
==========================================
- Coverage   82.24%   81.44%   -0.81%     
==========================================
  Files         302      292      -10     
  Lines       39585    38865     -720     
  Branches     6094     5794     -300     
==========================================
- Hits        32557    31653     -904     
- Misses       5691     5843     +152     
- Partials     1337     1369      +32

Impacted Files	Coverage Δ
tests/test_util_inspect.py	59.51% <0%> (-31.1%)	⬇️
sphinx/util/inspect.py	48.97% <16.66%> (-24.42%)	⬇️
sphinx/util/pycompat.py	47.14% <0%> (-42.86%)	⬇️
sphinx/pycode/__init__.py	78.66% <0%> (-9.34%)	⬇️
tests/test_pycode_parser.py	91.73% <0%> (-8.27%)	⬇️
tests/conftest.py	84.61% <0%> (-7.7%)	⬇️
tests/test_smartquotes.py	92.5% <0%> (-7.5%)	⬇️
tests/test_pycode.py	92.59% <0%> (-7.41%)	⬇️
... and 42 more

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[tk0miya]

LGTM.
I'd like to merge this into 1.7 branch. Could you rebase this please?

[terencehonles]

@tk0miya done!

[tk0miya]

Thank you for quick work!