No example for how to load animations by name

## How can Bevy's documentation be improved?

The [animated_fox](https://github.com/bevyengine/bevy/blob/6f56380826ce4641fccb672c92f5c97601041f4c/examples/animation/animated_fox.rs#L34) example shows how to load animations by path, but not by animation name.

By loading in the `Gltf` object directly and then debugging it, I was able to determine that I needed the path, not the animation name. However, no example of how I might use the animation name itself was found, despite it being substantially more human-readable.