Revert "Fix SyntaxError in guides sample code"

This reverts commit f573df32d43c413a5098721ba6151ff190c23c6c.

The original idea of this documentation was to showcase the feature
where you can remove some only queries attributes with a single
key-value pair.

guides/source/active_record_querying.md

@@ -711,7 +711,7 @@ Post.order('id DESC').limit(20).unscope(:order, :limit) = Post.all
 You can additionally unscope specific where clauses. For example:
 
 ```ruby
-Post.where(id: 10).limit(1).unscope(:where, :limit).order('id DESC') = Post.order('id DESC')
+Post.where(id: 10).limit(1).unscope({ where: :id }, :limit).order('id DESC') = Post.order('id DESC')
 ```
 
 ### `only`