Rename retired features to retiring features in toc

Author: mhko

articles/ai-services/speech-service/toc.yml

@@ -477,9 +477,9 @@ items:
           href: /rest/api/batchtexttospeech/operation-groups
         - name: Batch avatar REST API
           href: /rest/api/batchavatar/operation-groups
-- name: Retired features and migration
+- name: Retiring features and migration
   items:
-  - name: Retiring Features
+  - name: Retiring features
     displayName: migrate,migration,deprecate,retire,sunset
     items:
       - name: Speaker recognition