Improves UX a bit and should provide prettier previews
when / if doc links are shared around.

* commit '65802a7ebcd0b661c829307354ab0c24e1e05031':
  Squashed 'json/' changes from 4cfead7ba..6eaf7dff4

6eaf7dff4 Merge pull request #586 from handrews/dollar-schema
b5270c56e Update all draft-next $schema, $id, $ref.
dd343685e Copy remotes to draft-next without changes.
8919ce99b Add $schema to optional/format 2019-09 tests
d88c04ff5 Add $schema for optional/format 2020-12
da237da59 draft-specific 2020-12 remotes, $refs, and $ids
0eb6893f4 draft-specific 2019-09 remotes, $refs, and $ids
c0ba85b60 Remove accidental duplication
e8851f1a9 Add "$schema" to all document roots
8d653be4d Copy remotes to draft dirs, no changes yet
113a08e5c Optional tests for no $schema (2019-09+)
909835901 Update README to reflect $schema detection
be49e5b07 Add $schema to all 2019-09 tests
64793fe67 Add $schema for all 2020-12 tests.

git-subtree-dir: json
git-subtree-split: 6eaf7dff43b81e78bd10658b3dd917bf0b345ab1

ed0b855e7 Merge pull request #594 from json-schema-org/differing-uris
ae0651398 Merge pull request #593 from json-schema-org/gregsdennis-propertyDependencies-tests
0ba0976d8 more varied test cases
b78035ee5 Merge branch 'gregsdennis-propertyDependencies-tests' of github.com:json-schema-org/JSON-Schema-Test-Suite into gregsdennis-propertyDependencies-tests
8c2b46f7a rework functional tests to better illustrate purpose of keyword
33d9c6486 Update tests/draft-next/propertyDependencies.json
de3f7691f Add tests for some more differing URI scenarios.
e59510507 additional 'ignore' tests with nested matches
fc6cee5ab propertyDependencies non-string property value tests
99f3b60c1 add basic propertyDependencies tests

git-subtree-dir: json
git-subtree-split: ed0b855e7ea80c37d9295002fe436c01d9c65230

* commit 'f5f839a5995c8005373214271989daae3537d70e':
  Squashed 'json/' changes from 6eaf7dff4..ed0b855e7

Passes a few more of the just-added upstream tests (and in particular
is a last URN $id-related fix).

One test still fails which is waiting for more tweaks to how remote ref
lookups are done.

Format support / enablement will change with vocabulary support,
but in the interim, now that #905 is merged, these objects are
better accessed by retrieving them directly from the corresponding
validator.

In other words: don't do:

    from jsonschema import draft202012_format_checker

just do

    from jsonschema import Draft202012Validator
    do_whatever_with(Draft202012Validator.FORMAT_CHECKER)