add short description on top of pages

src/modules/users/Users.tsx

@@ -1,4 +1,9 @@
 /* eslint-disable react-hooks/exhaustive-deps */
+/**
+ * This page shows a table of all users. It is only available for Admin users.
+ *
+ * Admin users can add one or more users, or edit a user.
+ */
 import React, { useState, useCallback, useEffect, useMemo } from 'react';
 import { SearchIcon, PlusIcon, ViewGridAddIcon } from '@heroicons/react/solid';
 import { CogIcon, TrashIcon } from '@heroicons/react/outline';