This feature makes it possible to workaround problems such as:
- long baking time due to heavy synchronization when parsing geometry
from mesh instances
- crash when freeing `NavigationMeshInstance` while baking
- errors when actively baking node tree is being detached from the
scene tree
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.
For the time being we don't support writing a description for those, preferring
having all details in the method's description.
Using self-closing tags saves half the lines, and prevents contributors from
thinking that they should write the argument or return documentation there.
