Update toc.yml

Updating file name

Author: KendalBond007

articles/healthcare-apis/toc.yml

@@ -21,7 +21,7 @@ items:
     - name: Business continuity & disaster recovery
       href: business-continuity-disaster-recovery.md
     - name: Regional availability of services & features
-      href: services-features-availability-zones.md
+      href: services-features-regional-availability.md
     - name: Availability zones
       href: availability-zones.md
     - name: Manage network access security