code: function getRight(node) {
      let right = node.right;
  
      while (isConcatenation(right)) {
          right = right.left;
      }
      return right;
  }
docs: Get's the left most node on the right side of a BinaryExpression with + operator.
  @param {ASTNode} node - A BinaryExpression node to check.
  @returns {ASTNode} node