Fix a typo in ConnectionPoool#connection deprecation

Author: byroot

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

@@ -295,8 +295,8 @@ def lease_connection
 
       def connection
         ActiveRecord.deprecator.warn(<<~MSG)
-          ConnectionPoool#connection is deprecated and will be removed
-          in Rails 7.3. Use #lease_connection instead
+          ActiveRecord::ConnectionAdapters::ConnectionPoool#connection is deprecated
+          and will be removed in Rails 7.3. Use #lease_connection instead.
         MSG
         lease_connection
       end