refactor: use official user guide URLs

Author: kenjis

app/Views/welcome_message.php

@@ -214,7 +214,7 @@
                 <button id="menuToggle">&#9776;</button>
             </li>
             <li class="menu-item hidden"><a href="#">Home</a></li>
-            <li class="menu-item hidden"><a href="https://codeigniter4.github.io/userguide/" target="_blank">Docs</a>
+            <li class="menu-item hidden"><a href="https://codeigniter.com/user_guide/" target="_blank">Docs</a>
             </li>
             <li class="menu-item hidden"><a href="https://forum.codeigniter.com/" target="_blank">Community</a></li>
             <li class="menu-item hidden"><a
@@ -264,7 +264,7 @@
 
         <p>The User Guide contains an introduction, tutorial, a number of "how to"
             guides, and then reference documentation for the components that make up
-            the framework. Check the <a href="https://codeigniter4.github.io/userguide"
+            the framework. Check the <a href="https://codeigniter.com/user_guide/"
             target="_blank">User Guide</a> !</p>
 
         <h2>

system/Debug/Toolbar/Views/_config.tpl

@@ -1,5 +1,5 @@
 <p class="debug-bar-alignRight">
-    <a href="https://codeigniter4.github.io/CodeIgniter4/index.html" target="_blank" >Read the CodeIgniter docs...</a>
+    <a href="https://codeigniter.com/user_guide/" target="_blank" >Read the CodeIgniter docs...</a>
 </p>
 
 <table>

system/Session/Handlers/BaseHandler.php

@@ -41,7 +41,7 @@ abstract class BaseHandler implements SessionHandlerInterface
      * Cookie prefix
      *
      * The Config\Cookie::$prefix setting is completely ignored.
-     * See https://codeigniter4.github.io/CodeIgniter4/libraries/sessions.html#session-preferences
+     * See https://codeigniter.com/user_guide/libraries/sessions.html#session-preferences
      *
      * @var string
      */