Remove unused instrumentation hooks from action_controller

Instrumentation hooks for `write_page.action_controller` and
`expire_page.action_controller` seem to be removed
in https://github.com/rails/rails/pull/7833.
So, subscribers for them are no longer necessary.

actionpack/lib/action_controller/log_subscriber.rb

@@ -62,8 +62,7 @@ module ActionController
       end
     end
 
-    %w(write_fragment read_fragment exist_fragment?
-       expire_fragment expire_page write_page).each do |method|
+    %w(write_fragment read_fragment exist_fragment? expire_fragment).each do |method|
       class_eval <<-METHOD, __FILE__, __LINE__ + 1
         def #{method}(event)
           return unless logger.info? && ActionController::Base.enable_fragment_cache_logging

guides/source/active_support_instrumentation.md

@@ -156,30 +156,6 @@ Within the Ruby on Rails framework, there are a number of hooks provided for com
 }
 ```
 
-#### write_page.action_controller
-
-| Key     | Value             |
-| ------- | ----------------- |
-| `:path` | The complete path |
-
-```ruby
-{
-  path: '/users/1'
-}
-```
-
-#### expire_page.action_controller
-
-| Key     | Value             |
-| ------- | ----------------- |
-| `:path` | The complete path |
-
-```ruby
-{
-  path: '/users/1'
-}
-```
-
 #### start_processing.action_controller
 
 | Key           | Value                                                     |