docs: added pre-orders guide (#12984)

* docs: added pre-orders guide

* fix lint errors

www/apps/resources/generated/generated-commerce-modules-sidebar.mjs

@@ -6102,6 +6102,14 @@ const generatedgeneratedCommerceModulesSidebarSidebar = {
               "path": "https://docs.medusajs.com/resources/how-to-tutorials/tutorials/loyalty-points",
               "children": []
             },
+            {
+              "loaded": true,
+              "isPathHref": true,
+              "type": "ref",
+              "title": "Implement Pre-Orders",
+              "path": "https://docs.medusajs.com/resources/how-to-tutorials/tutorials/preorder",
+              "children": []
+            },
             {
               "loaded": true,
               "isPathHref": true,
@@ -11477,6 +11485,14 @@ const generatedgeneratedCommerceModulesSidebarSidebar = {
               "path": "https://docs.medusajs.com/resources/examples/guides/custom-item-price",
               "children": []
             },
+            {
+              "loaded": true,
+              "isPathHref": true,
+              "type": "ref",
+              "title": "Implement Pre-Order Products",
+              "path": "https://docs.medusajs.com/resources/how-to-tutorials/tutorials/preorder",
+              "children": []
+            },
             {
               "loaded": true,
               "isPathHref": true,