Document Godot project file format comments

project.godot

@@ -1,6 +1,10 @@
 ; Engine configuration file.
 ; It's best edited using the editor UI and not directly,
 ; since the parameters that go here are not all obvious.
+;
+; Format:
+;   [section] ; section goes between []
+;   param=value ; assign values to parameters
 
 config_version=5