Update REST API links to point to the official Microsoft documentation

Author: Mukesh Dua

articles/microsoft-discovery/index.yml

@@ -115,4 +115,4 @@ landingContent:
       - linkListType: reference
         links:
           - text: REST API
-            url: /rest/api/discovery/
+            url: https://learn.microsoft.com/rest/api/discovery/

articles/microsoft-discovery/overview-service-architecture.md

@@ -1,5 +1,5 @@
 ---
-title: Service Architecture Overview
+title: Microsoft Discovery service architecture overview
 description: An overview of Microsoft Discovery's Service Architecture
 author: DaveMuhich
 ms.author: damuhic

articles/microsoft-discovery/toc.yml

@@ -249,4 +249,4 @@ items:
   - name: Reference
     items:
       - name: REST API
-        href: /rest/api/discovery/
+        href: https://learn.microsoft.com/rest/api/discovery/