PhysicsBody now has methods move_and_collide/test_move and needed
properties for these methods: safe margin, locked axes (3D only).
Moved collision_exceptions from StaticBody to PhysicsBody for 3D
(same as 2D, and conforms to documentation).
RigidBody doesn't have test_motion method anymore, it's now redundant
with PhysicsBody.test_move.
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.
- 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
