fixup! Replace link to doxygen with link to guides and fix link to deprecated doxygen pages

Author: LasseRosenow

_includes/header.html

@@ -20,7 +20,7 @@
               <li><a href="{% link index.html %}#use-cases">Use Cases</a></li>
               <li><a href="https://www.hackster.io/riot-os" target="_blank">[email protected]<i class="bi bi-box-arrow-up-right align-text-bottom"></i></a></li>
               <li><a href="{% link index.html %}#faq">FAQ</a></li>
-              <li><a href="https://guide.riot-os.org/" target="_blank">Documentation <i class="bi bi-box-arrow-up-right align-text-bottom"></i></a></li>
+              <li><a href="https://guide.riot-os.org/" target="_blank">Guides <i class="bi bi-box-arrow-up-right align-text-bottom"></i></a></li>
               <li><a href="https://doc.riot-os.org/" target="_blank">API Documentation <i class="bi bi-box-arrow-up-right align-text-bottom"></i></a></li>
             </ul>
           </li>

index.html

@@ -272,7 +272,7 @@ <h4 class="pt-3">Get the code</h4>
               <div class="card border-0">
                 <div class="card-body">
                   <i class="ri-file-text-line me-2 fs-2"></i>
-                  <h4 class="pt-3">Read the documentation</h4>
+                  <h4 class="pt-3">Read our guides</h4>
                 </div>
               </div>
             </a>