Document VALUES as table value constructor

When I search for VALUES in the KB, I only find a page for the function VALUES/VALUE, with a note that starting from 10.3.3 it's not what it used to be; but it doesn't say what it has become.

It needs to be documented in all roles it plays now, including being a standalone statement like

MariaDB [test]> values(1);

+---+

| 1 |

+---+

| 1 |

+---+

1 row in set (0.00 sec)