Add "Unused Parameters" to the documentation

Author: allanrenucci

docs/sidebar.yml

@@ -53,6 +53,8 @@ sidebar:
               url: docs/reference/auto-parameter-tupling.html
             - title: Named Type Arguments
               url: docs/reference/named-typeargs.html
+            - title: Unused Parameters
+              url: docs/reference/unused-parameters.html
             - title: Local Optimisations
               url: docs/reference/optimisations.html
         - title: Changed Features