Update Import2 API Doc

Author: DeLioncourtLestat

index.html

@@ -92,6 +92,7 @@
                             <li><a href="/#authentication">Authentication</a></li>
                             <li><a href="/#sandbox">Sandbox</a></li>
                             <li><a href="/#response-codes">Response Codes and Errors</a></li>
+                            <li><a href="/#rate-limits">API Rate Limits</a></li>
                             <li><a href="/#get-tools">GET /tools</a></li>
                             <li><a href="/#post-imports">POST /imports</a></li>
                             <li><a href="/#get-imports">GET /imports</a></li>