src/vs/editor/common/model/bracketPairsTextModelPart/bracketPairsTree/ast.ts/Immutable23ListAstNode/toMutable
class Immutable23ListAstNode:	override toMutable(): ListAstNode {
		return new TwoThreeListAstNode(this.length, this.listHeight, this.item1, this.item2, this.item3, this.missingOpeningBracketIds);
	}