Detect erroneous JSON(B) encoding
Detect erroneous JSON(B) encoding

JSON(B) automatically marshals any value. Avoid marshalling values of
pgtype.JSON and pgtype.JSONB. The caller certainly meant to call on a
pointer.

See https://github.com/jackc/pgx/issues/350 for discussion.

refs #350

jackc/pgx,jackc/pgx,jackc/pgx,jackc/pgx