These classes have dozens of open bugs and missing features
which may not be fixed anytime soon.
It's probably better to document it upfront at this point.
(cherry picked from commit 0493e7c106)
We already removed it from the online docs with #35132.
Currently it can only be "Built-In Types" (Variant types) or "Core"
(everything else), which is of limited use.
We might also want to consider dropping it from `ClassDB` altogether
in Godot 4.0.
Follow-up to #31925, `<member />` tags just before `</members>` would cause
a parsing issue, and we'd never notice that we're no longer parsing members.
Also added space before closing `/>`.
- Document a few more properties and methods
- Add more information to many classes
- Fix lots of typos and gramar mistakes
- Use [code] tags for parameters consistently
- Use [b] and [i] tags consistently
- Put "Warning:" and "Note:" on their own line to be more visible,
and make them always bold
- Tweak formatting in code examples to be more readable
- Use double quotes consistently
- Add more links to third-party technologies
All 100% completed: MainLoop, Node, Object, Path, Performance,
Reference, Resource, SceneState, SceneTree, UndoRedo.
Also fixed some en_GB occurrences as the reference spelling is en_US.
