And fill in some known-good and known-bad examples. We can make this
as detailed as we want, but this commit just adds enough to know that:
* The full-file spec examples are valid.
* The JSON Schema can distinguish valid examples from invalid JSON.
This will help catch JSON Schema typos like those being addressed by
[1].
[1]: https://github.com/opencontainers/runtime-spec/pull/784
Signed-off-by: W. Trevor King <wking@tremily.us>
W. Trevor King