DOC: consistent docstring for compression kwarg

[minggli]

• closes ENH: Add 'infer' option to compression in _get_handle() #17900
• tests added / passed
• passes git diff upstream/master -u -- "*.py" | flake8 --diff

#17900 (comment) removed zip from docstring. But the support to write zip compression was added during March and April this year (mainly #20394 and a few patches) and now in functional and in production.

Because #17900 started when there is no zip writing and merged after zip writing support is added, it appears to have inadvertently changed docstring. This PR disambiguates and reflects production.

import os
import pandas as pd

a = pd.DataFrame(10000 * [[123, 234, 435]], columns=['A', 'B', 'C'])
a.to_csv('test_compressed', index=False, compression='zip')
b = pd.read_csv('test_compressed', compression='zip')

assert a.equals(b)
os.remove('test_compressed')

>>> pd.__version__
'0.23.3'

[codecov]

Codecov Report

Merging #22066 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #22066   +/-   ##
=======================================
  Coverage   92.05%   92.05%           
=======================================
  Files         170      170           
  Lines       50708    50708           
=======================================
  Hits        46677    46677           
  Misses       4031     4031

Flag	Coverage Δ
#multiple	90.45% <ø> (ø)	⬆️
#single	42.36% <ø> (ø)	⬆️

Impacted Files	Coverage Δ
pandas/core/generic.py	96.47% <ø> (ø)	⬆️
pandas/core/frame.py	97.19% <ø> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update be6ad72...54e1526. Read the comment docs.

[jreback]

thanks @minggli