Reword sentence

Sentence had some awkward grammar and was kind of confusing, tried to make it easier
to understand what it was trying to say :)

[ci skip]

guides/source/active_record_migrations.md

@@ -973,9 +973,9 @@ that Active Record supports. This could be very useful if you were to
 distribute an application that is able to run against multiple databases.
 
 NOTE: `db/schema.rb` cannot express database specific items such as triggers,
-sequences, stored procedures or check constraints, etc. While in a migration you
-can execute custom SQL statements, the schema dumper cannot reconstitute those
-statements from the database. If you are using features like this, then you
+sequences, stored procedures or check constraints, etc. Please note that while
+custom SQL statements can be run in migrations, these statements cannot be reconstituted
+by the schema dumper. If you are using features like this, then you
 should set the schema format to `:sql`.
 
 Instead of using Active Record's schema dumper, the database's structure will