Those signals receive either a PhysicsBody2D or a TileMap object,
and what the emitting method checks internally is only that the
object is a Node. In theory any Node could go through these signals
if they talk directly to the PhysicsServer2D.
Also updated docs.
Fixes#27076.
Might need further (compat breaking) improvement as this API is a
bit confusing, cf. #24739.
f34c8015cb