notifications: allow viewing stack trace of unexpected error

Previously, it was only possible to view the stack trace by clicking
the copy button and pasting it somewhere.

src/utils/react.ts

@@ -1,6 +1,7 @@
 // helper functions for React components
 
-import React from 'react';
+import React, { useState } from 'react';
+import { createCountFunc } from './iter';
 
 /**
  * Callback that can be passed to onContextMenu event handlers to prevent
@@ -11,3 +12,17 @@ export const preventBrowserNativeContextMenu: React.MouseEventHandler = (e) =>
 
 /** Style to disable pointer events. */
 export const pointerEventsNone: React.CSSProperties = { pointerEvents: 'none' };
+
+const nextId = createCountFunc();
+
+/**
+ * React hook to get a unique identifier, e.g. for linking components via
+ * aria-labelledby.
+ *
+ * @param prefix A namespace prefix for the identifier.
+ * @returns A unique identifier in the form "prefix-N"
+ */
+export const useUniqueId = (prefix: string): string => {
+    const [uniqueId] = useState(`${prefix}-${nextId()}`);
+    return uniqueId;
+};