Update 'Get started' link to new URL

Author: juntao

index.html

@@ -841,7 +841,7 @@
                     <a href="#features">Features</a>
                     <a href="#benefits">Benefits</a>
                     <a href="#opensource">Open Source</a>
-                    <a href="https://echokit.dev/docs/quick-start">Get started</a>
+                    <a href="https://echokit.dev/docs/category/quick-start">Get started</a>
                 </div>
             </nav>
         </header>