This fixes the issue with labels being cut off (or becoming too long
when not clipped).
This also adds a mention of the individual cell size,
which is useful information to have when trying to avoid light leaking
or particle collision tunneling.
* GIProbe is now VoxelGI
* BakedLightmap is now LightmapGI
As godot adds more ways to provide GI (as an example, SDFGI in 4.0), the different techniques (which have different pros/cons) need to be properly named to avoid confusion.