Add enable="on" to set compression command (#9811)

docs/compression/README.md

@@ -27,11 +27,16 @@ Default config includes most common highly compressible content extensions and m
 $ mc admin config set myminio compression extensions=".pdf" mime_types="application/pdf"
 ```
 
-To enable compression for all content, with default extensions and mime-types.
+To show help on setting compression config values.
 ```
 ~ mc admin config set myminio compression
 ```
 
+To enable compression for all content, with default extensions and mime-types.
+```
+~ mc admin config set myminio compression enable="on"
+```
+
 The compression settings may also be set through environment variables. When set, environment variables override the defined `compress` config settings in the server config.
 
 ```bash