COMPAT: PySlice_GetIndicesEx is a macro on PyPy

[mattip]

the fix for issue #15961 broke compatibility with PyPy. This pull request fixes it (fixed formatting for linter)

[codecov]

Codecov Report

Merging #16194 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #16194      +/-   ##
==========================================
+ Coverage   90.86%   90.86%   +<.01%     
==========================================
  Files         162      162              
  Lines       50862    50862              
==========================================
+ Hits        46215    46216       +1     
+ Misses       4647     4646       -1

Flag	Coverage Δ
#multiple	88.64% <ø> (ø)	⬆️
#single	40.3% <ø> (ø)	⬆️

Impacted Files	Coverage Δ
pandas/core/common.py	91.03% <0%> (+0.34%)	⬆️

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[jreback]

thanks!