Lightmap outdated information for Godot 4.1

[m-decoster]

Your Godot version: 4.1

Issue description: The information to set up LightMapGI still refers to Godot 3 settings and node names and it is outdated.

URL to the documentation page: https://docs.godotengine.org/en/stable/tutorials/3d/global_illumination/using_lightmap_gi.html#doc-using-lightmap-gi

For example, under "Setting up meshes", this screenshot is shown, but these settings do not exist in Godot 4.