Fixes Moon & Star set bonus.
Fixes the set bonus from Moon and Star. The special_on_hit.fct
bit of its damage had a misinterpreted argument: the first argument is not self
but the weapon's combat
table. Luckily the combat table now has a reference to the source as of MR !693 (merged).
This MR is save safe, but old copies of the items will still have the broken behavior.