Update Vector2.angle() description

doc/base/classes.xml

@@ -37501,6 +37501,8 @@ This method controls whether the position between two cached points is interpola
 			<return type="float">
 			</return>
 			<description>
+			Returns the result of atan2 when called with the Vector's x and y as parameters (Math::atan2(x,y)).
+			Be aware that it therefore returns an angle oriented clockwise with regard to the (0, 1) unit vector, and not an angle oriented counter-clockwise with regard to the (1, 0) unit vector (which would be the typical trigonometric representation of the angle when calling Math::atan2(y,x)).
 			</description>
 		</method>
 		<method name="angle_to">