Fixed typo [ci skip]

singular is more suited to

guides/source/layouts_and_rendering.md

@@ -1121,11 +1121,11 @@ With this change, you can access an instance of the `@products` collection as th
 You can also pass in arbitrary local variables to any partial you are rendering with the `locals: {}` option:
 
 ```erb
-<%= render partial: "products", collection: @products,
+<%= render partial: "product", collection: @products,
            as: :item, locals: {title: "Products Page"} %>
 ```
 
-Would render a partial `_products.html.erb` once for each instance of `product` in the `@products` instance variable passing the instance to the partial as a local variable called `item` and to each partial, make the local variable `title` available with the value `Products Page`.
+Would render a partial `_product.html.erb` once for each instance of `product` in the `@products` instance variable passing the instance to the partial as a local variable called `item` and to each partial, make the local variable `title` available with the value `Products Page`.
 
 TIP: Rails also makes a counter variable available within a partial called by the collection, named after the member of the collection followed by `_counter`. For example, if you're rendering `@products`, within the partial you can refer to `product_counter` to tell you how many times the partial has been rendered. This does not work in conjunction with the `as: :value` option.