DOC: How to partition domains

Add instructions to developer documentation about initializing git submodules
before local build.

We don't preserve non-native byte-order and we have no wish to do so.
(If someone disagrees, they better wite a NEP ;))
Spell it out, and thus:

closes gh-1866

Co-authored-by: Sebastian Berg <sebastianb@nvidia.com>

The docs seem to be collapsing `--` into `-`, leading the live [page](https://numpy.org/devdocs/user/troubleshooting-importerror.html) to show an invalid command:
```
pip install numpy –upgrade
```

This adds backticks to force both of the `-`'s to be visible

Also add links to this document from the functions' docstrings.