[ci skip] Clarify the doc for creating links:

- We mention how `*_path` works with various examples and suddenly
  use a code snippet that don't use the `*_path`.

  Modified the doc to use `product_path(product.id)`, to make
  it explicit. While it's longer, it's clearer, especially since
  we are in the "getting started guide"

  I don't think mentioning how `link_to(product)` works is a good
  idea in this guide, the `link_to` accepts a crazy amount of
  different values with many heuristics to determine the url to
  generate. This is documented in the action view guide and in
  the API.
  Let's keep it simple in the Getting Started guide.

  Fix rails#54162

Author: Edouard-chin

guides/source/getting_started.md

@@ -1100,7 +1100,7 @@ Let's refactor this to use these helpers:
 <div id="products">
   <% @products.each do |product| %>
     <div>
-      <%= link_to product.name, product %>
+      <%= link_to product.name, product_path(product.id) %>
     </div>
   <% end %>
 </div>
@@ -1147,7 +1147,7 @@ We can update `app/views/products/index.html.erb` to link to the new action.
 <div id="products">
   <% @products.each do |product| %>
     <div>
-      <%= link_to product.name, product %>
+      <%= link_to product.name, product_path(product.id) %>
     </div>
   <% end %>
 </div>