Update inverted index docs

[mgartner]

Marcus Gartner (mgartner) commented:

The [inverted index docs](https://www.cockroachlabs.com/docs/stable/inverted-indexes#arrays] do not list all operators for which inverted indexes on ARRAYs and JSON can be used.

Arrays

The following operators in filters can use inverted indexes on an ARRAY-type column:

• is contained by <@ (already mentioned in docs)
• contains @> (already mentioned in docs)
• overlaps &&
  • Do the two arrays have any elements in common?
  • Ex: array_col && ARRAY['foo', 'bar')

JSON

• is contained by <@ (already mentioned in docs)
• contains @> (already mentioned in docs)
• equals = (already mentioned in docs)
• exist ?
  • Does the string exist as a top-level key within the JSON value?
  • Ex: json_col ? 'foo'
• some/any exists ?|
  • Do any of the strings in the array exist as top-level keys?
  • Ex: json_col ?| ARRAY['foo', 'bar']
• all exists ?&'
  • Do all of the strings in the array exist as top-level keys?
  • Ex: json_col ?& ARRAY['foo', 'bar']

It might be worth noting that some more complex JSON expressions with the fetch value operator, ->, can also be index-accelerated. Some examples:

SELECT * FROM t WHERE json_col->'foo' = '123'::JSON;

SELECT * FROM t WHERE json_col->0->'foo' = '123'::JSON;

SELECT * FROM t WHERE json_col->'foo' @> '[1, 2, 3]'::JSON;

SELECT * FROM t where json_col->'foo' IN ('[1, 2, 3]'::JSON, '{"a": "b"}'::JSON);

Jira Issue: DOC-9133