BUG #10498: documented function json_each(jsonb) is missing.

The following bug has been logged on the website:

Bug reference:      10498
Logged by:          Matthew Schinckel
Email address:      matt@schinckel.net
PostgreSQL version: 9.4beta1
Operating system:   Mac OS X
Description:

http://www.postgresql.org/docs/9.4/static/functions-json.html#FUNCTIONS-JSON-PROCESSING-TABLE,
row 2 indicates this function should be there. Executing it shows
otherwise.

matt=# SELECT json_each('{"a":1}'::json);
 json_each
-----------
 (a,1)
(1 row)

matt=# SELECT json_each('{"a":1}'::jsonb);
ERROR:  function json_each(jsonb) does not exist
LINE 1: SELECT json_each('{"a":1}'::jsonb);
               ^
HINT:  No function matches the given name and argument types. You might need
to add explicit type casts.