Update Animation.track_set_path and AnimationMixer.root_motion_track

Updated the usage description of [method Animation.track_set_path] and [member Animation.root_motion_track] to identify the parent is the root_node identified in animation player, and that the format is the same for each.

Remove extra symbols

doc/classes/Animation.xml

@@ -560,7 +560,7 @@
 			<param index="0" name="track_idx" type="int" />
 			<param index="1" name="path" type="NodePath" />
 			<description>
-				Sets the path of a track. Paths must be valid scene-tree paths to a node and must be specified starting from the parent node of the node that will reproduce the animation. Tracks that control properties or bones must append their name after the path, separated by [code]":"[/code].
+				Sets the path of a track. Paths must be valid scene-tree paths to a node and must be specified starting from the [member AnimationMixer.root_node] that will reproduce the animation. Tracks that control properties or bones must append their name after the path, separated by [code]":"[/code].
 				For example, [code]"character/skeleton:ankle"[/code] or [code]"character/mesh:transform/local"[/code].
 			</description>
 		</method>

doc/classes/AnimationMixer.xml

@@ -304,8 +304,8 @@
 			This makes it more convenient to preview and edit animations in the editor, as changes to the scene will not be saved as long as they are set in the reset animation.
 		</member>
 		<member name="root_motion_track" type="NodePath" setter="set_root_motion_track" getter="get_root_motion_track" default="NodePath(&quot;&quot;)">
-			The path to the Animation track used for root motion. Paths must be valid scene-tree paths to a node, and must be specified starting from the parent node of the node that will reproduce the animation. To specify a track that controls properties or bones, append its name after the path, separated by [code]":"[/code]. For example, [code]"character/skeleton:ankle"[/code] or [code]"character/mesh:transform/local"[/code].
-			If the track has type [constant Animation.TYPE_POSITION_3D], [constant Animation.TYPE_ROTATION_3D] or [constant Animation.TYPE_SCALE_3D] the transformation will be canceled visually, and the animation will appear to stay in place. See also [method get_root_motion_position], [method get_root_motion_rotation], [method get_root_motion_scale] and [RootMotionView].
+			The path to the Animation track used for root motion. Paths must be valid scene-tree paths to a node, and must be specified starting from the parent node of the node that will reproduce the animation. The [member root_motion_track] uses the same format as [method Animation.track_set_path], but note that a bone must be specified.
+			If the track has type [constant Animation.TYPE_POSITION_3D], [constant Animation.TYPE_ROTATION_3D], or [constant Animation.TYPE_SCALE_3D] the transformation will be canceled visually, and the animation will appear to stay in place. See also [method get_root_motion_position], [method get_root_motion_rotation], [method get_root_motion_scale], and [RootMotionView].
 		</member>
 		<member name="root_node" type="NodePath" setter="set_root_node" getter="get_root_node" default="NodePath(&quot;..&quot;)">
 			The node which node path references will travel from.