[4.0] EditorImportPlugin info is no longer correct

**Your Godot version:**
4.0-beta4

**Issue description:**
- ```_get_import_options``` and ```_get_option_visibility``` have been changed to take a resource path as an additional argument in godotengine/godot@cd2a4990844fac72ae624a51bb797716e69ce2c3. The class reference has been updated, but the topmost example (mesh importer) not, in neither GDScript nor C#.
- ```_get_priority``` and ```_get_import_order``` mention default values, implying that those functions do not have to be overridden. This is true in Godot 3.x, but godotengine/godot@3682978aee06cd5cf26ba462a4e44d352e9e0cd1 made the default implementations print errors. (Although I'm not sure if that was intended?)

**URL to the documentation page:**