... from flutter/flutter/docs/engine to flutter/engine/docs.

We would also need to update the links in https://github.com/flutter/flutter/wiki/Supporting-legacy-platforms.

The longer we choose not to do this, the more chance folks bookmark or otherwise expect the files to be in the framework repo, so my two cents is we should just bite the bullet and move them. I can volunteer to do the move and update the links, but I want to make sure both of you are OK with this plan first.

I think moving the docs is preferred for multiple reasons:

• The engine team owns the docs, and we work in the engine repo
• It's good to be able to make atomic changes to the docs and code at the same time
• Being able to cross-reference the docs will become easier within the same repo

Can I get an explicit LGTM?