NumPy doc cross links

[joshmoore]

The question arose at the EOSS kickoff meeting whether it would be possible to make a suggestion for the numpy io documentation (https://numpy.org/devdocs/reference/routines.io.html) for use of zarr as a (eventually the preferred?) mechanism for persisting numpy arrays. Text is needed for the top under "Input and Output" at the top as well a block dedicated to Zarr down below. Minimally a PR against https://github.com/numpy/numpy/blob/master/doc/source/reference/routines.io.rst is needed, but there may be other locations that need cross-referencing.

cc: @rgommers @zarr-developers/core-devs

[rgommers]

Thanks @joshmoore. This would be great, just a mention in routines.io.rst would be a good start.

I have opened numpy/numpy#15760 for the bigger topic of adding a nice How-To guide to the NumPy docs on how to deal with array data storage. Thoughts there on content for that How-To are very welcome.

I'm starting to put together more relative well-fleshed-out doc proposals like that for NumPy so we have more interesting documentation / educational materials work that people interested in that can engage with.