Merge pull request rails#47251 from zzak/psql-move-comment-to-note

Move comment to out of codeblock to note

Author: zzak

guides/source/active_record_postgresql.md

@@ -315,7 +315,6 @@ To add a new value (before or after an existing one) or to rename a value you sh
 
 ```ruby
 # db/migrate/20150720144913_add_new_state_to_articles.rb
-# NOTE: ALTER TYPE ... ADD VALUE cannot be executed inside of a transaction block so here we are using disable_ddl_transaction!
 disable_ddl_transaction!
 
 def up
@@ -326,6 +325,8 @@ def up
 end
 ```
 
+NOTE: `ALTER TYPE ... ADD VALUE` cannot be executed inside of a transaction block so here we are using `disable_ddl_transaction!`
+
 NOTE: Enum values [can't be dropped or reordered](https://www.postgresql.org/docs/current/datatype-enum.html). Adding a value is not easily reversed.
 
 Hint: to show all the values of the all enums you have, you should call this query in `bin/rails db` or `psql` console: