Add note about inertia being required for apply_torque on various Nodes

- RigidBody2D
  - PhysicsDirectBodyState2D
  - RigidBody3D
  - PhysicsDirectBodyState3D

doc/classes/PhysicsDirectBodyState2D.xml

@@ -76,6 +76,7 @@
 			<param index="0" name="torque" type="float" />
 			<description>
 				Applies a rotational force without affecting position. A force is time dependent and meant to be applied every physics update.
+				[b]Note:[/b] [member inverse_inertia] is required for this to work. To have [member inverse_inertia], an active [CollisionShape2D] must be a child of the node, or you can manually set [member inverse_inertia].
 			</description>
 		</method>
 		<method name="apply_torque_impulse">
@@ -84,6 +85,7 @@
 			<description>
 				Applies a rotational impulse to the body without affecting the position.
 				An impulse is time-independent! Applying an impulse every frame would result in a framerate-dependent force. For this reason, it should only be used when simulating one-time impacts (use the "_force" functions otherwise).
+				[b]Note:[/b] [member inverse_inertia] is required for this to work. To have [member inverse_inertia], an active [CollisionShape2D] must be a child of the node, or you can manually set [member inverse_inertia].
 			</description>
 		</method>
 		<method name="get_constant_force" qualifiers="const">

doc/classes/PhysicsDirectBodyState3D.xml

@@ -76,6 +76,7 @@
 			<param index="0" name="torque" type="Vector3" />
 			<description>
 				Applies a rotational force without affecting position. A force is time dependent and meant to be applied every physics update.
+				[b]Note:[/b] [member inverse_inertia] is required for this to work. To have [member inverse_inertia], an active [CollisionShape3D] must be a child of the node, or you can manually set [member inverse_inertia].
 			</description>
 		</method>
 		<method name="apply_torque_impulse">
@@ -84,6 +85,7 @@
 			<description>
 				Applies a rotational impulse to the body without affecting the position.
 				An impulse is time-independent! Applying an impulse every frame would result in a framerate-dependent force. For this reason, it should only be used when simulating one-time impacts (use the "_force" functions otherwise).
+				[b]Note:[/b] [member inverse_inertia] is required for this to work. To have [member inverse_inertia], an active [CollisionShape3D] must be a child of the node, or you can manually set [member inverse_inertia].
 			</description>
 		</method>
 		<method name="get_constant_force" qualifiers="const">

doc/classes/RigidBody2D.xml

@@ -87,6 +87,7 @@
 			<param index="0" name="torque" type="float" />
 			<description>
 				Applies a rotational force without affecting position. A force is time dependent and meant to be applied every physics update.
+				[b]Note:[/b] [member inertia] is required for this to work. To have [member inertia], an active [CollisionShape2D] must be a child of the node, or you can manually set [member inertia].
 			</description>
 		</method>
 		<method name="apply_torque_impulse">
@@ -95,6 +96,7 @@
 			<description>
 				Applies a rotational impulse to the body without affecting the position.
 				An impulse is time-independent! Applying an impulse every frame would result in a framerate-dependent force. For this reason, it should only be used when simulating one-time impacts (use the "_force" functions otherwise).
+				[b]Note:[/b] [member inertia] is required for this to work. To have [member inertia], an active [CollisionShape2D] must be a child of the node, or you can manually set [member inertia].
 			</description>
 		</method>
 		<method name="get_colliding_bodies" qualifiers="const">

doc/classes/RigidBody3D.xml

@@ -87,6 +87,7 @@
 			<param index="0" name="torque" type="Vector3" />
 			<description>
 				Applies a rotational force without affecting position. A force is time dependent and meant to be applied every physics update.
+				[b]Note:[/b] [member inertia] is required for this to work. To have [member inertia], an active [CollisionShape3D] must be a child of the node, or you can manually set [member inertia].
 			</description>
 		</method>
 		<method name="apply_torque_impulse">
@@ -95,6 +96,7 @@
 			<description>
 				Applies a rotational impulse to the body without affecting the position.
 				An impulse is time-independent! Applying an impulse every frame would result in a framerate-dependent force. For this reason, it should only be used when simulating one-time impacts (use the "_force" functions otherwise).
+				[b]Note:[/b] [member inertia] is required for this to work. To have [member inertia], an active [CollisionShape3D] must be a child of the node, or you can manually set [member inertia].
 			</description>
 		</method>
 		<method name="get_colliding_bodies" qualifiers="const">