Rename "Contribute" section of docs to "Development"?

[TomNicholas]

What is your issue?

We recently changed the layout of the docs, and now there is a section in the top-level bar called "Contribute". But this section also contains a lot of other important information, such as all the docs on Xarray Internals, and the Development Roadmap.

As those pages aren't really about contributing, but contributing is about development, I propose we rename this heading to "Development" instead.

[scottyhq]

Yeah, could certainly have gone with either heading, "Contribute" seemed good to me and @dcherian
#8708 (comment)

I like your "Developer Guide" top-level though perhaps call it "Contribute" (low-confidence suggestion)

Also @benbovy had some further ideas about this #8708 (comment)

It's out of scope of this PR and may be addressed later, but IMO the "Contribute > Xarray internals" section could be reworked as currently it looks a bit like a catch-all section. More specifically, the pages about extending Xarray (accessors, IO backends, indexes...) could be more visible too. Perhaps move these into a new "Advanced Guide" or "Extending Xarray" top-level section? Technically those pages can be viewed as "contributing" to the Xarray ecosystem, but I rather view the "Contribute" section (and "Xarray internals") as helping to contribute to Xarray itself.

For reference this is the current structure:

Happy to help out with further docs cleanup depending on preferences!