Refresh 404 page on the website. (#8069)

The redesign was many months ago now.
diff --git a/docs/website/overrides/404.html b/docs/website/overrides/404.html
index b26e210..bcd1da4 100644
--- a/docs/website/overrides/404.html
+++ b/docs/website/overrides/404.html
@@ -8,16 +8,7 @@
 
 <p>Sorry, we couldn't find that page.</p>
 
-<p>
-  We recently redesigned this website. You may find what you are searching for at
-<ul>
-  <li>The <a href="https://github.com/google/iree/tree/main/docs/developers"><code>docs/developers/</code></a>
-    directory on GitHub for developer-focused documentation</li>
-  <li>The previously published <a
-      href="https://github.com/google/iree/tree/99c6ce409783eaffb37dd46f3f4a6ef761556f99/docs"><code>gh-pages</code>
-      branch</a> for the full set of old pages</li>
-</ul>
-</p>
+<p>The <a href="https://github.com/google/iree/tree/main/docs/developers"><code>docs/developers/</code></a> directory on GitHub might be helpful.
 
 <p>Click <a href="{{ config.site_url }}">here</a> to go back to the home page.</p>