[docs] Be consistent about how much information we include about elastic.co/guide

[colleenmcginnis]

We have two guides on where people can contribute to the docs: Contribute locally and Contribute on the web. In Contribute on the web we cover contributing to both elastic.co/guide AND elastic.co/docs. In Contribute locally we only cover elastic.co/docs.

How much information should we be including about elastic.co/guide in these docs? Should we limit the docs in docs-builder to information about docs-builder with notes that link off to other places for information about elastic.co/guide? Or should we document these processes side-by-side?

[bmorelli25]

I think the purpose of these docs has changed over time. When written, V3 hadn't been released yet and we wanted to specifically call out the differences between creating content in the old system and the new system. I'd agree that it's time to remove any /guide specifics from these docs.