Docs readme update

[alexander-l-stone]

• Helps with Improve doc/README.rst #23084
• No tests added / passed
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
• Modified the process for updating forks in docs/README.rst to use git merge instead of git rebase. Also added the git command for setting upstream to pandas.

[WillAyd]

Thanks for the PR! Do you also want to update the README to account for the non-functional python make.py build line?

[WillAyd]

Since this is really something that only ever needs to be done once would be better separated out

[TomAugspurger]

This all seems duplicative of the contributing page. How about we extract what isn't in there already and just change doc/README.rst to a link pointing to that?

[codecov]

Codecov Report

Merging #23097 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #23097   +/-   ##
=======================================
  Coverage    92.2%    92.2%           
=======================================
  Files         169      169           
  Lines       50924    50924           
=======================================
  Hits        46952    46952           
  Misses       3972     3972

Flag	Coverage Δ
#multiple	90.62% <ø> (ø)	⬆️
#single	42.3% <ø> (ø)	⬆️

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[datapythonista]

+1 on what @TomAugspurger says. I personally wouldn't even bother on having a README in docs/, but if we have one, I'd just link to the contributing page.

[TomAugspurger]

I suggested a link to the contributing docs to not break links, but I assume people don't expect URLs pointing inside the tree of a git repo to be around forever.

…

On Fri, Oct 12, 2018 at 4:27 PM Marc Garcia ***@***.***> wrote: +1 on what @TomAugspurger <https://github.com/TomAugspurger> says. I personally wouldn't even bother on having a README in docs/, but if we have one, I'd just link to the contributing page. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#23097 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABQHIsmIA2o0SnyH_uXXkCT9NBMBDiJyks5ukQk9gaJpZM4XYgsG> .

[jreback]

@alexander-l-stone can you update to @TomAugspurger suggestion.

[datapythonista]

Closing as stale. @alexander-l-stone if you want to continue working on it, please reopen or create a new PR, and refer to #23828.