Godot-docs: Always redirect user to latest docs

[tavurth]

Your Godot version:

3.2.1.stable.official

Issue description:

When arriving from Google, I very often find myself on an outdated docs page.

I propose rewriting the users request to always point to the latest doc, unless that doc has significantly changed from the version the user is trying to access.

Example:

1. I'd like to access the information about InputMap
2. I go to Google and type "Godot InputMap"
3. I arrive at the 3.1 docs page and have to click through to the latest version every time.

At the moment this isn't much of an issue since the 3.1 and 3.2 docs are different colors, and I can tell that I need to redirect to get the latest docs.

But what if I want the old docs?

If the previous page and the next page have vastly different modification times then it makes sense the user might want the old docs, as the Godot API may have changed by this time.

[pycbouh]

This should already be fixed by #3422, but search engines will take time to update.

since the 3.1 and 3.2 docs are different colors

Surely this banner is also indicative 🙂

[tavurth]

This should already be fixed by #3422, but search engines will take time to update.

Great, glad to hear it!

Surely this banner is also indicative 🙂

The links from google can sometimes lead to a subheading or portion of the document, so this bar may not always be visible.

An example

[mhilbrunner]

Currently the plan is to always link to /stable/ (so 3.2 currently) by default, not /latest/.
This should hopefully be the case after the latest changes we did are deployed everywhere and Google's index is refreshed.

So I'll close this as a duplicate of the issues mentioned in https://github.com/godotengine/godot-docs/pull/3422 for now. :) But thanks for taking the time to file an issue!