Changed the chapters order (#1146)

Switched canvas_layers and 2d_transforms to fit the order in the text.

tutorials/2d/index.rst

@@ -5,8 +5,8 @@
    :maxdepth: 1
    :name: toc-learn-features-2d
 
-   2d_transforms
    canvas_layers
+   2d_transforms
    using_tilemaps
    custom_drawing_in_2d
    particle_systems_2d