src/vs/workbench/api/browser/mainThreadCustomEditors.ts/MainThreadCustomEditorModel/redo
class MainThreadCustomEditorModel:	private async redo(): Promise<void> {
		if (!this._editable) {
			return;
		}

		if (this._currentEditIndex >= this._edits.length - 1) {
			// nothing to redo
			return;
		}

		const redoneEdit = this._edits[this._currentEditIndex + 1];
		this.change(() => {
			++this._currentEditIndex;
		});
		await this._proxy.$redo(this._editorResource, this.viewType, redoneEdit, this.isDirty());
	}