Update Exchange Server TOC

retire 2013 article and add 2016/2019 article

Author: KCCross

Exchange/ExchangeServer/servertoc/toc.yml

@@ -102,8 +102,8 @@ items:
           href: ../administration/insufficient-access-rights-perform-operation.md
         - name: EWS App pool crashes
           href: ../administration/ews-app-pool-crashes.md
-        - name: Exchange 2013 end of support roadmap
-          href: ../administration/exchange-2013-end-of-support.md
+        - name: Exchange Server 2016 and 2019 end of support roadmap
+          href: ../administration/exchange-2016-2019-end-of-support.md
         - name: Exchange CU installation fails
           href: ../administration/cannot-install-exchange-cu-localized-windows.md
         - name: Fail to add mailbox database copy