Texture Atlas migration should be complete

[IQuick143]

Problem

The migration regarding TextureAtlas tells the user to use an UiImage.

However a later section reveals that UiImage has been replaced and should be changed to ImageNode

Solution

The section for TextureAtlas should either explain the full migration, or at least point directly to the next step.

[miketwenty1]

For anyone else finding this: https://docs.rs/bevy/latest/bevy/prelude/struct.ImageNode.html ImageNode is apparently is the way.