DOC: Accessing files from a S3 bucket.

[myles]

Add some documentation about accessing files from a remote S3 bucket in pandas.

• closes DOC: improve s3 access doc-strings / docs #12206
• tests added / passed
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
• whatsnew entry

[codecov]

Codecov Report

Merging #23639 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #23639      +/-   ##
==========================================
- Coverage   92.24%   92.24%   -0.01%     
==========================================
  Files         161      161              
  Lines       51326    51314      -12     
==========================================
- Hits        47347    47335      -12     
  Misses       3979     3979

Flag	Coverage Δ
#multiple	90.63% <ø> (-0.01%)	⬇️
#single	42.31% <ø> (-0.02%)	⬇️

Impacted Files	Coverage Δ
pandas/io/common.py	70.54% <0%> (-0.23%)	⬇️
pandas/io/parquet.py	84.61% <0%> (-0.15%)	⬇️
pandas/io/html.py	91.2% <0%> (-0.06%)	⬇️
pandas/core/series.py	93.68% <0%> (-0.03%)	⬇️
pandas/io/json/json.py	93.09% <0%> (-0.02%)	⬇️
pandas/core/frame.py	97.02% <0%> (-0.01%)	⬇️
pandas/io/parsers.py	95.55% <0%> (-0.01%)	⬇️
pandas/tseries/offsets.py	97.07% <0%> (-0.01%)	⬇️
pandas/core/groupby/ops.py	96.79% <0%> (ø)	⬆️
pandas/plotting/_core.py	83.63% <0%> (ø)	⬆️
... and 4 more

---

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[alimcmaster1]

NIT: But I think this should read 'Pandas supports loading files'

[alimcmaster1]

This looks good to me - CC. @jreback and @datapythonista

[datapythonista]

We already have this: https://pandas.pydata.org/pandas-docs/stable/io.html#reading-remote-files

I'd expand that section if there is anything missing, I wouldn't expect many people to look in the cookbook for S3 options having a page specific for IO operations.

Does it make sense?

[myles]

@datapythonista I've expanded the the section in io and remove it from cookbook.

[datapythonista]

Thanks for updating @myles. That looks good to me, but I don't know much about S3, so will let other people review.

[jreback]

thanks!