extensions/markdown-language-features/src/languageFeatures/diagnostics.ts/LinkWatcher/startWatching
class LinkWatcher:	private startWatching(path: vscode.Uri): vscode.Disposable {
		const watcher = vscode.workspace.createFileSystemWatcher(new vscode.RelativePattern(path, '*'), false, true, false);
		const handler = (resource: vscode.Uri) => this.onLinkedResourceChanged(resource);
		return vscode.Disposable.from(
			watcher,
			watcher.onDidDelete(handler),
			watcher.onDidCreate(handler),
		);
	}