Change the instructions for writing the API

Godot API is such a mess: 1000 lines of Python to parse XML that outputs rst
to feed the sphinx...

CONTRIBUTING.md

@@ -9,9 +9,13 @@ commit will..."
 ## Coding Style
 
 The program is written in Godot's scripting language GDScript. We follow here 
-the 
-[style guide](https://docs.godotengine.org/en/latest/getting_started/\scripting/gdscript/gdscript_styleguide.html)
-described in Godot Documentation.
+the [style guide] described in Godot Documentation.
 
-When creating a class or a function, describe it in the API chapter of the documentation
-The API follows the same style as [Godot API](https://docs.godotengine.org/en/latest/classes/index.html)
+## API
+
+When creating a class or a function, describe it in the API chapter of the 
+documentation. Use the object description directives. If you are doing a scene
+prefix the name with `class-` and use lowercase and separate words with `-`.
+Do not forget to indicate signals.
+
+[style guide]: https://docs.godotengine.org/en/latest/getting_started/scripting/gdscript/gdscript_styleguide.html