Use a more descriptive menu name

ref:
https://docs.civicrm.org/dev/en/latest/documentation/style-guide/#describing-the-civicrm-user-interface

mkdocs.yml

@@ -207,7 +207,7 @@ pages:
   - Backbone Reference: framework/backbone.md
   - Cache Reference: framework/cache.md
   - CiviMail: 
-     - Overview: framework/civimail/index.md
+     - CiviMail: framework/civimail/index.md
      - Tokens: framework/civimail/tokens.md
   - CiviReport: framework/civireport.md
   - Codebase: framework/codebase.md