message: Fix editing of npc background traits
diff: <<set _class += '<</listbox>>'>>
  <<set _background to '<<listbox "$npcs[$currentPassage.key].background" autoselect>>'>>
  - <<for _key range Object.keys(setup.npcData.backgroundTraits)>>
  + <<for _key range Object.keys(lib.backgroundTraits)>>
  <<set _background += '<<option "' + _key + '" "' + _key + '">>'>>
  <</for>>
  <<set _background += '<</listbox>>'>>
  