This PR implements:
* A new hint: PROPERTY_HINT_NODE_TYPE for variant type OBJECT, which can take specific node types as hint string.
* The editor will show it as a node path, but will set it as a pointer to a node from the current scene if you select a path.
* When scene is saved, the node path is saved, then restored as a pointer.
NOTE: This is a proof of concept and this approach will most likely not work. The reason if that, if the node referenced is deleted, then when trying to edit this the node will become invalid.
Potential workarounds: Since this uses the Variant API, it should obtain the pointer from the Variant object ID. Yet, this would either only really work in GDScript or it would need to be implemented with workarounds in every language.
Alternative ways to make this work: Nodes could export an additional property with a node path (like for which_node, it could be which_node_path).
Another alternative: Path editing could happen as a hidden metadata (ignoring the pointer).
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.
* New syntax is type safe.
* New syntax allows for type safe virtuals in native extensions.
* New syntax permits extremely fast calling.
Note: Everything was replaced where possible except for `_gui_input` `_input` and `_unhandled_input`.
These will require API rework on a separate PR as they work different than the rest of the functions.
Added a new method flag METHOD_FLAG_OBJECT_CORE, used internally. Allows to not dump the core virtuals like `_notification` to the json API, since each language will implement those as it is best fits.
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.
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
