feat(docs): navigation with left/right arrow keys

[ydcjeff]

Fixes #{issue number}

Description:

• Add navigation_with_keys config to be able to visit the docs with left/right arrow keys (HTML doc: navigate with left/right arrow keys sphinx-doc/sphinx#2064)
• Fix WARNING docstring

https://deploy-preview-1726--pytorch-ignite-preview.netlify.app

Check list:

• New tests are added (if a new feature is added)
• New doc strings: description and/or example code are in RST format
• Documentation is updated (if required)

[vfdev-5]

@ydcjeff thanks for the PR ! Do you like how it works ?

I tried this feature and find it a bit strange ...

• if you do only left left ... it changes between quick-start and main page alternatively

[ydcjeff]

I like tho tbh.
Yes, I tried left and left, it goes between quick-start and index page
Yes, it happens to this site also : https://pydata-sphinx-theme.readthedocs.io/en/latest/index.html

[vfdev-5]

Thanks for the reference on pydata and seems like pandas also uses that. Why not!

[vfdev-5]

Thanks for making our docs modern :)