fix transform_camera image not showing up

tutorials/3d/using_transforms.rst

@@ -108,6 +108,7 @@ This is also an analog to a 3x3 identity matrix.
 Following the OpenGL convention, ``X`` is the *Right* axis, ``Y`` is the *Up* axis and ``Z`` is the *Forward* axis.
 
 Together with the *basis*, a transform also has an *origin*. This is a *Vector3* specifying how far away from the actual origin ``(0, 0, 0)`` this transform is. Combining the *basis* with the *origin*, a *transform* efficiently represents a unique translation, rotation, and scale in space.
+
 .. image:: img/transforms_camera.png