Clarify Curve.get_closest_point uses baked points.

Based on the doc, I wasn't sure if get_closest_point would return the
closest baked point or the closest "source" point. It seems to use
baked:
https://github.com/godotengine/godot/blob/8faecd6a470aeef41084a32d74f4a131a5ef42b6/scene/resources/curve.cpp#L809

(cherry picked from commit ef5042a70f9d9ef1ac8292fc2a00a1560eecd182)

doc/classes/Curve2D.xml

@@ -63,7 +63,7 @@
 			<argument index="0" name="to_point" type="Vector2">
 			</argument>
 			<description>
-				Returns the closest point (in curve's local space) to [code]to_point[/code].
+				Returns the closest baked point (in curve's local space) to [code]to_point[/code].
 				[code]to_point[/code] must be in this curve's local space.
 			</description>
 		</method>

doc/classes/Curve3D.xml

@@ -78,7 +78,7 @@
 			<argument index="0" name="to_point" type="Vector3">
 			</argument>
 			<description>
-				Returns the closest point (in curve's local space) to [code]to_point[/code].
+				Returns the closest baked point (in curve's local space) to [code]to_point[/code].
 				[code]to_point[/code] must be in this curve's local space.
 			</description>
 		</method>