Deprecate jsonschema.draftN_format_checker attributes.v4.16.0

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)

1 files changed, 1 insertions, 1 deletions

diff --git a/docs/validate.rst b/docs/validate.rst
index f949837..9f88259 100644
--- a/docs/validate.rst
+++ b/docs/validate.rst
@@ -181,7 +181,7 @@ By default, no validation is enforced, but optionally, validation can be enabled
     >>> validate(
     ...     instance="-12",
     ...     schema={"format" : "ipv4"},
-    ...     format_checker=draft202012_format_checker,
+    ...     format_checker=Draft202012Validator.FORMAT_CHECKER,
     ... )
     Traceback (most recent call last):
         ...