Document `message` argument to table constructor of `box.error.new`

[TarantoolBot]

Related dev. issue(s): tarantool/tarantool#9102

Product: Tarantool
Since: 3.1
Root document: https://www.tarantool.io/en/doc/latest/reference/reference_lua/box_error/new/
SME: @ CuriousGeorgiy

Details

Link to the design document
Requested by @ CuriousGeorgiy in tarantool/tarantool@a19aac8.