Escape parameters named `enum`.
Escape parameters named `enum`.

Prefix parameters named `enum` with an underscore like all the other
reserved keywords.

godotengine/godot-cpp,godotengine/godot-cpp,GodotNativeTools/cpp_bindings,GodotNativeTools/cpp_bindings,godotengine/godot-cpp,godotengine/godot-cpp