Add note to SceneTree about pausing

This pull request adds a small amendment to `SceneTree` describing the behavior `_physics_process()` when pausing the scene.

`_physics_process` will completely stop processing collisions and signals whenever the scene is paused, however, the function will still receive calls.

This addresses: godotengine#47326

(cherry picked from commit d62175e)

doc/classes/SceneTree.xml

@@ -246,7 +246,7 @@
 		</member>
 		<member name="paused" type="bool" setter="set_pause" getter="is_paused" default="false">
 			If [code]true[/code], the [SceneTree] is paused. Doing so will have the following behavior:
-			- 2D and 3D physics will be stopped.
+			- 2D and 3D physics will be stopped. This includes signals and collision detection.
 			- [method Node._process], [method Node._physics_process] and [method Node._input] will not be called anymore in nodes.
 		</member>
 		<member name="refuse_new_network_connections" type="bool" setter="set_refuse_new_network_connections" getter="is_refusing_new_network_connections" default="false">