DEV: Hand-pick Rails/WhereNot autofixes (#35117)

We can't enable `Rails/WhereNot` lint/autofix, because it would break
code that uses mini_sql instead of AR (which rubocop, and tbh also we,
can't easily differentiate)

Those are safe because they either:
* are executed in AR model scope definitions
* are clearly chained starting from a AR model
* are less-clearly chained, but still can be traced to a AR model/scope

---------

Co-authored-by: Loïc Guitaut <loic@discourse.org>

plugins/discourse-post-voting/spec/lib/topic_view_spec.rb

@@ -179,7 +179,7 @@ describe TopicView do
         TopicView.new(
           topic.id,
           user,
-          post_number: topic.posts.where("deleted_at IS NOT NULL").pick(:post_number),
+          post_number: topic.posts.where.not(deleted_at: nil).pick(:post_number),
         )
 
       expect(near_view.desired_post.id).to eq(post.id)