Fix HTML- and URL-encoding bugs on homepage

tildes/tildes/templates/base.jinja2

@@ -130,7 +130,7 @@
     <li class="site-footer-link"><a href="https://blog.tildes.net">Blog</a></li>
     <li class="site-footer-link"><a href="https://docs.tildes.net/contact">Contact</a></li>
     <li class="site-footer-link"><a href="https://gitlab.com/tildes/tildes">Source code</a></li>
-    <li class="site-footer-link"><a href="https://gitlab.com/tildes/tildes/issues?label_name[]=Feature+Request&label_name[]=Stage%3A%3AAccepted&scope=all&sort=priority&state=opened">Planned features</a> / <a href="https://gitlab.com/tildes/tildes/issues">All issues</a></li>
+    <li class="site-footer-link"><a href="https://gitlab.com/tildes/tildes/issues?label_name%5B%5D=Feature+Request&amp;label_name%5B%5D=Stage%3A%3AAccepted&amp;scope=all&amp;sort=priority&amp;state=opened">Planned features</a> / <a href="https://gitlab.com/tildes/tildes/issues">All issues</a></li>
     <li class="site-footer-link"><a href="https://docs.tildes.net/policies/privacy-policy">Privacy policy</a></li>
     <li class="site-footer-link"><a href="https://docs.tildes.net/policies/terms-of-use">Terms of use</a></li>
   </ul>