extensions/references-view/src/references/model.ts/FileItem/asCopyText
class FileItem:	async asCopyText() {
		let result = `${vscode.workspace.asRelativePath(this.uri)}\n`;
		for (const ref of this.references) {
			result += `  ${await ref.asCopyText()}\n`;
		}
		return result;
	}