Using non-uniform scale is known to cause many issues.
Add warnings to the editor and to the class reference.
Also remove the warning from SoftBody3D since it is
not relevant there: it simulates in global space.
- Document using convex decomposition in the editor.
- Mention that "trimesh" is synonymous with a concave collision shape.
- Add performance hints for each collision shape.
This makes it easier to spot syntax errors when editing the
class reference. The schema is referenced locally so validation
can still work offline.
Each class XML's schema conformance is also checked on GitHub Actions.
