Merge branch 'moon_star_fix' into 'master'

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.

**This MR is save safe, but old copies of the items will still have the broken behavior.**

See merge request !801