Remove deprecated ActiveRecord::ConnectionAdapters::ConnectionPool#connection_klass

Author: rafaelfranca

activerecord/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Remove deprecated `ActiveRecord::ConnectionAdapters::ConnectionPool#connection_klass`.
+
+    *Rafael Mendonça França*
+
 *   Remove deprecated support to apply `#connection_pool_list`, `#active_connections?`, `#clear_active_connections!`,
     `#clear_reloadable_connections!`, `#clear_all_connections!` and `#flush_idle_connections!` to the connections pools
     for the current role when the `role` argument isn't provided.

activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb

@@ -220,8 +220,6 @@ def unpin_connection! # :nodoc:
       def connection_class # :nodoc:
         pool_config.connection_class
       end
-      alias :connection_klass :connection_class
-      deprecate :connection_klass, deprecator: ActiveRecord.deprecator
 
       # Returns true if there is an open connection being used for the current thread.
       #

guides/source/7_2_release_notes.md

@@ -154,6 +154,8 @@ Please refer to the [Changelog][active-record] for detailed changes.
     `#clear_reloadable_connections!`, `#clear_all_connections!` and `#flush_idle_connections!` to the connections pools
     for the current role when the `role` argument isn't provided.
 
+*   Remove deprecated `ActiveRecord::ConnectionAdapters::ConnectionPool#connection_klass`.
+
 ### Deprecations
 
 *   Deprecate `Rails.application.config.active_record.allow_deprecated_singular_associations_name`