Restructure

docs/hooks/cms/cms.md

-# Overview
-
-In earlier versions of CiviCRM hooks were packaged in different formats depending on the CMS.  These methods can still be used but the CMS-agnostic [extensions](/extensions/index.md) are the preferred method.
-
-The documentation here on the CMS-specific methods is for historical reference.

docs/hooks/index.md

@@ -43,7 +43,7 @@ function myextension_civicrm_buildForm($formName, &$form) {
 
 This works well in many cases but has its limitations.  For example, if two extensions call the same hook there is no way to determine which runs first.
 
-For details, see [Tradtional Hooks](/hooks/traditional.md)
+For details, see [Tradtional Hooks](/hooks/usage/extension.md)
 
 ### Symfony method
 
@@ -59,7 +59,7 @@ function myextension_buildForm($event) {
 }
 ```
 
-For more details see [Hooks with Symfony](/hooks/symfony.md)
+For more details see [Hooks with Symfony](/hooks/usage/symfony.md)
 
 ## Targeting Certain Events
 

mkdocs.yml

@@ -59,13 +59,11 @@ pages:
 - Hooks:
   - Hooks Introduction: hooks/index.md
   - Usage:
-    - Traditional Hooks: hooks/traditional.md
-    - Hooks with Symfony: hooks/symfony.md
-  - Legacy CMS Hooks:
-    - CMS Hooks: hooks/cms/cms.md
-    - Hooks with Joomla: hooks/cms/joomla.md
-    - Hooks with Drupal: hooks/cms/drupal.md
-    - Hooks with WordPress: hooks/cms/wordpress.md
+    - Hooks in Extensions: hooks/usage/extension.md
+    - Hooks in Symfony: hooks/usage/symfony.md
+    - Hooks in Drupal: hooks/usage/drupal.md
+    - Hooks in Joomla: hooks/usage/joomla.md
+    - Hooks in WordPress: hooks/usage/wordpress.md
   - All Hooks: hooks/list.md
   - Batch Hooks:
     - hook_civicrm_batchItems: hooks/hook_civicrm_batchItems.md