DOC: Cleanup for nbsphinx output

[TomAugspurger]

Followup to #15581

Using the nbsphinx: hidden metadata to hide the ouptut, so
readers don't see matplotlib's fc-list warning.

Make the tables monospaced in CSS.

[TomAugspurger]

@jreback is this what you meant by aligned?

My change made them use monospace font, but doesn't apply any additional styling.

[jreback]

hmm maybe need to right align the numbers
i thought we do that by default

[TomAugspurger]

We probably do in the notebook, but this is picking up the CSS from the website. I'll right-align in the CSS.

[TomAugspurger]

Fixed

[codecov]

Codecov Report

Merging #15951 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #15951   +/-   ##
=======================================
  Coverage   90.99%   90.99%           
=======================================
  Files         145      145           
  Lines       49570    49570           
=======================================
  Hits        45106    45106           
  Misses       4464     4464

Flag	Coverage Δ
#multiple	88.76% <ø> (ø)	⬆️
#single	40.56% <ø> (ø)	⬆️

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[codecov]

Codecov Report

Merging #15951 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #15951      +/-   ##
==========================================
+ Coverage   90.99%   90.99%   +<.01%     
==========================================
  Files         145      145              
  Lines       49570    49570              
==========================================
+ Hits        45106    45107       +1     
+ Misses       4464     4463       -1

Flag	Coverage Δ
#multiple	88.76% <ø> (ø)	⬆️
#single	40.56% <ø> (ø)	⬆️

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

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[jreback]

@TomAugspurger great! yeah to be honest we should prob default right-align / and fixed decimals for the first thing in the notebook (or I think its the default)?

merge away

[jreback]

thanks @TomAugspurger

[jreback]

font looks nice, though warnings are still there :<

[TomAugspurger]

Ah shoot. Looks like you actually have to import matplotlib.pyplot to trigger it (I don't see it locally). I'm doing another PR touching the notebook, I'll throw the fix in there.