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.
Adds ability to add error return documetation to the binder and class reference.
Usage example:
```C++
void MyClass::_bind_method() {
[..]
BIND_METHOD_ERR_RETURN_DOC("load", ERR_FILE_CANT_OPEN, ERR_FILE_UNRECOGNIZED);
}
```
One function of ConfigFile was changed as example.
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
Found via `codespell -q 3 --skip="./thirdparty,./editor/translations" -I ../godot-word-whitelist.txt`
Whitelist consists of:
```
ang
doubleclick
lod
nd
que
te
unselect
```
