message: Remove `MoraleModifier` constructor
  Since members are public, this is covered by aggregate initialization.
  Less maintenance if the compiler handles this case automatically.
diff: @@ -9,9 +9,6 @@ struct MoraleModifier
  {
  public:
  MoraleModifier() = default;
  - MoraleModifier(int rBonus, int pBonus, int fRate, int mRate) :
  - researchBonus(rBonus), productionBonus(pBonus), fertilityRate(fRate), mortalityRate(mRate)
  - {}
  int researchBonus{0};
  int productionBonus{0};
  