Editor from master branch should always show at the latest docs instead docs for 3.0 version

[qarmin]

Godot version:
3.1 master

Issue description:
When I click at the top of editor at Help -> Online Docs, then a web browser opens site docs.godotengine.org which redirects to docs.godotengine.org/en/3.0/ instead docs.godotengine.org/en/latest/.

When I checked source code I found a lot of links that redirect to obsolete documentation.

Other branch should change "latest" word to itself version (e.g. 3.2 version docs.godotengine.org/en/3.2/)