more Ruby 1.9 Hash syntax in our guides

guides/source/active_record_querying.md

@@ -707,7 +707,7 @@ 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 => :id, :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`

guides/source/asset_pipeline.md

@@ -707,7 +707,7 @@ config.assets.cache_store = :memory_store
 The options accepted by the assets cache store are the same as the application's cache store.
 
 ```ruby
-config.assets.cache_store = :memory_store, { :size => 32.megabytes }
+config.assets.cache_store = :memory_store, { size: 32.megabytes }
 ```
 
 Adding Assets to Your Gems