DOC: Getting started should have a quick-start example

[pllim]

"Getting Started" looks pretty sparse:

What happens after installation? Would be nice to actually have "getting started to use the package" example too, not just installation.

[WilliamJamieson]

There is no "quick-start" example here, asdf-astropy is just an extension library for asdf which provides the necessary extensions to serialize supported astropy objects. Any quick-start is equivalent to getting started with asdf (only with writing astropy specific objects, which is functionally the same as how asdf works with any other supported object when asdf-astropy is installed). Would a link to asdf's hello world be sufficient?

[pllim]

Hmm, perhaps that is sufficient or feel free to close if you think this request is not actionable.