The `GET_ARRAY` and `MEMBERS` modes were removed during development and
review of commit 8eab76eb84 (string(JSON): Adds JSON parsing support to
the string command, 2020-08-24, v3.19.0-rc1~159^2), but were
accidentally left in an error message.
Adds a set of sub commands to the string command for parsing JSON, the
JSON commands are: GET, TYPE, MEMBER, LENGTH, REMOVE, SET, and EQUAL.
Closes: #19501
