Apply suggestions from code review by Harry

Co-authored-by: Harry Percival <hjwp2@cantab.net>

Author: Xronophobe

chapter_15_advanced_forms.asciidoc

@@ -237,7 +237,7 @@ That long-winded model test did serendipitously help us find unexpected
 bugs, but now it's time to rewrite it. I wrote it in a very verbose style to
 introduce the Django ORM, but in fact, we can get the same coverage from a
 couple of much shorter tests.
-Delete `test_saving_and_retrieving_items` and replace with this:
+Delete `test_saving_and_retrieving_items` and replace it with this:
 
 [role="sourcecode"]
 .lists/tests/test_models.py (ch13l010)
@@ -346,18 +346,11 @@ The problem is that we have at least one database record which used to be valid
 but after introducing our new constraint, the `unique_together`, it's no longer
 compatible.
 
-Just delete `src/db.sqlite3` and run the migration again. We can do this,
-because it's only a dev environment, and the data saved in the database isn't
-important.
+To fix this problem, we can just delete `src/db.sqlite3` and run the migration again.
+We can do this because the database on our laptop is only used for dev, so the data in it is not important.
 
-However, if we already have records we want to keep (which would be the case in
-a production environment, where we need to keep our users' data) we would need
-to do a bit more work and come up with a migration strategy for dealing with
-invalid--duplicate in this case--records.
-// CSANAD: I wanted to mention some articles from credible sources explaining
-//         migration strategies, modifying migration scripts, etc
-//         but all I found were either outdated, or clearly chatgpt-generated
-// articles.
+In <chapter_deploying_validation>>, we'll deploy our new code to production,
+and discuss what to do if we run into migrations and data integrity issues at that point.
 
 Now if we change our duplicates test to do a `.save` instead of a
 `.full_clean`...
@@ -789,7 +782,7 @@ AssertionError: '' != "You've already got this in your list"
 
 The error message isn't being displayed because we are not using the Bootstrap
 classes. Although it would have been nice to minimise hand-written html and
-utilise Django instead, it seems like we need to bring back our custom
+use Django instead, it seems like we need to bring back our custom
 `<input>` and add a few attributes manually:
 
 [role="sourcecode"]