docs: improved cart documentation (#2027)

www/docs/sidebars.js

@@ -268,10 +268,6 @@ module.exports = {
                 }
               ]
             },
-            {
-              type: "doc",
-              id: "guides/carts-in-medusa",
-            },
             {
               type: "doc",
               id: "advanced/backend/migrations",
@@ -304,6 +300,10 @@ module.exports = {
               type: "doc",
               id: "advanced/storefront/how-to-implement-checkout-flow",
             },
+            {
+              type: "doc",
+              id: "guides/carts-in-medusa",
+            },
           ]
         }
       ]