ArrayAnimatorWCS slices API ordering

[DanRyanIrish]

Description

The ordering of the slices list input to ArrayAnimatorWCS is in WCS order. However, this is not stated in the docstring. Is this a bug? Should slices in fact be Numpy order to be consistent with the data array?

Expected vs Actual behavior

Steps to Reproduce

Code goes here

System Details

• SunPy Version:
• Astropy Version:
• Python Version:
• OS information:

[Cadair]

It follows WCSAxes which is wcs order, the current behaviour should be documented.

[dstansby]

@Cadair can you move this to mpl-animators?