Created operator.
Created operator.

Created String::operator+=(const wchar_t), that was mark as Todo.
GodotNativeTools/godot-cpp,godotengine/godot-cpp,GodotNativeTools/godot-cpp,GodotNativeTools/cpp_bindings,GodotNativeTools/godot-cpp,godotengine/godot-cpp,godotengine/godot-cpp,godotengine/godot-cpp,GodotNativeTools/cpp_bindings