Begins a new undo entry
This example creates a prop_physics, and adds it to Player's undo list.
When you need to override the undo messages for a spawnable entity inside
ENT:SpawnFunction(user, trace) and apply a custom text, calling
undo.Create() will not work and will in fact double the undo entries in the list pointing to the same entity created. Otherwise you will see
Scripted Entity (entity_class) when you create it. This is defined in commands.lua and you must return
nil, then add the remaining hooks and function calls to account for the missing stuff: