_addStep(step) {
    if (step != null) {
      // record step as procesed
      this._stepsProcessed.push(step);

      // add step to player's next node
      const nextBattleLogNode = this._shiftToNextBattleLogNode();
      if (nextBattleLogNode != null) {
        nextBattleLogNode.setStep(step);
        nextBattleLogNode.setVisible(true);
      }
    }
  }
Adds an entry immediately to the battle log from a step.