Update Quaternion.html

docs/api/en/math/Quaternion.html

@@ -179,6 +179,8 @@
 
 		<h3>[method:Quaternion setFromRotationMatrix]( [param:Matrix4 m] )</h3>
 		<p>
+		[page:Matrix4 m] - a [page:Matrix4] of which the upper 3x3 of matrix is a pure
+		[link:https://en.wikipedia.org/wiki/Rotation_matrix rotation matrix] (i.e. unscaled).<br />
 		Sets this quaternion from rotation component of [page:Matrix4 m].<br />
 		Adapted from the method [link:http://www.euclideanspace.com/maths/geometry/rotations/conversions/matrixToQuaternion/index.htm here].
 		</p>