renamed file; added toc entry

Author: KarlErickson

…les/spring-cloud/how-to-customize-app.md …re-health-probes-graceful-termination.mdarticles/spring-cloud/how-to-customize-app.md renamed to articles/spring-cloud/how-to-configure-health-probes-graceful-termination.md articles/spring-cloud/how-to-customize-app.md renamed to articles/spring-cloud/how-to-configure-health-probes-graceful-termination.md

@@ -199,6 +199,8 @@ items:
       href: how-to-elastic-apm-java-agent-monitor.md
     - name: Analyze logs with ELK
       href: how-to-elastic-diagnostic-settings.md
+    - name: Health probes and graceful termination
+      href: how-to-configure-health-probes-graceful-termination.md
   - name: Network
     items:
     - name: Deploy Azure Spring Apps in a virtual network