Update doc and website references to new domain (#856)

www/reference/README.md

@@ -1,3 +1,3 @@
 # Medusa Docs
 
-Visit: docs.medusa-commerce.com to browse docs.
+Visit: docs.medusajs.com to browse docs.

www/reference/src/components/topbar.js

@@ -100,7 +100,7 @@ const Topbar = ({ data, api }) => {
           justifyContent: "flex-end",
         }}
       >
-        <Link variant="topbar" mr={3} href="https://docs.medusa-commerce.com">
+        <Link variant="topbar" mr={3} href="https://docs.medusajs.com">
           Docs
         </Link>
         <Link