These docs are woefully out of date. Let's remove the inaccuracies.

This patch does not add a lot of content or fancy examples. If we want to do that, lets do it as another issue.

The goal here is just to remove inaccuracies and keep things minimal.

It also adds instanceof operator (it made documenting easier, as we then support all of java's ops). It works for primitive types too, as we don't make any distinction there.