run metadata schemas through tskit.canonical_json( )

[petrelharp]

Next time there's an opportunity, we should adjust the metadata schemas so that they agree with the output of tskit.canonical_json(). This will avoid various headaches like this one tskit-dev/tskit#3244.

[bhaller]

Huh, ok. Perhaps you can provide a fix PR that (a) fixes the existing schemas, and (b) adds a new trees test that checks each schema and, if there is a problem, prints out a message that contains the fixed schema that can just be copy/pasted into SLiM? If this canonical_json() function is available on the C side then I'm happy to do such things myself, just point me to the C function to call; in that case I can write the check/print test myself in SLiM. But it sounds like this is a Python-only phenomenon (?), and so a Python-based check and fix is needed, so then it'd be great if you could do it. :->