docs: added a swap conceptual guide (#3888)

* docs: added a swap conceptual guide

* fix link type

* added text

www/docs/sidebars.js

@@ -722,12 +722,9 @@ module.exports = {
           label: "Orders",
         },
         {
-          type: "link",
-          href: "#",
+          type: "doc",
+          id: "modules/orders/swaps",
           label: "Swaps",
-          customProps: {
-            sidebar_is_soon: true,
-          },
         },
         {
           type: "link",