move configuration node to be peer with basics

Author: greg-lindsay

articles/application-gateway/toc.yml

@@ -35,20 +35,20 @@
       href: how-application-gateway-works.md
     - name: Application Gateway components
       href: application-gateway-components.md
-    - name: Configuration
-      items:
-      - name: Overview
-        href: configuration-overview.md
-      - name: Infrastructure
-        href: configuration-infrastructure.md
-      - name: Frontend IP address
-        href: configuration-frontend-ip.md
-      - name: Listeners
-        href: configuration-listeners.md
-      - name: Request routing rules
-        href: configuration-request-routing-rules.md
-      - name: HTTP settings
-        href: configuration-http-settings.md
+  - name: Configuration
+    items:
+    - name: Overview
+      href: configuration-overview.md
+    - name: Infrastructure
+      href: configuration-infrastructure.md
+    - name: Frontend IP address
+      href: configuration-frontend-ip.md
+    - name: Listeners
+      href: configuration-listeners.md
+    - name: Request routing rules
+      href: configuration-request-routing-rules.md
+    - name: HTTP settings
+      href: configuration-http-settings.md
   - name: Routing
     items:
     - name: Multi-site hosting