src/vs/workbench/browser/parts/editor/editor.contribution.ts/appendEditorToolItem
function appendEditorToolItem(primary: IEditorToolItem, when: ContextKeyExpression | undefined, order: number, alternative?: IEditorToolItem, precondition?: ContextKeyExpression | undefined): void {
	const item: IMenuItem = {
		command: {
			id: primary.id,
			title: primary.title,
			icon: primary.icon,
			precondition
		},
		group: 'navigation',
		when,
		order
	};

	if (alternative) {
		item.alt = {
			id: alternative.id,
			title: alternative.title,
			icon: alternative.icon
		};
	}

	MenuRegistry.appendMenuItem(MenuId.EditorTitle, item);
}