src/vs/editor/common/model/bracketPairsTextModelPart/bracketPairsTree/ast.ts/ArrayListAstNode/unappendChild
class ArrayListAstNode:	public unappendChild(): AstNode | undefined {
		this.throwIfImmutable();
		const item = this._children.pop();
		this.handleChildrenChanged();
		return item;
	}