doc: remove duplicate section

Fixes #3750.

doc/api/cluster.markdown

@@ -242,18 +242,6 @@ Example:
 
 Spawn a new worker process. This can only be called from the master process.
 
-## cluster.settings
-
-* {Object}
-  * `exec` {String} file path to worker file.  Default: `__filename`
-  * `args` {Array} string arguments passed to worker.
-    (Default=`process.argv.slice(2)`)
-  * `silent` {Boolean} whether or not to send output to parent's stdio.
-    (Default=`false`)
-
-All settings set by the `.setupMaster` is stored in this settings object.
-This object is not supposed to be change or set manually.
-
 ## cluster.disconnect([callback])
 
 * `callback` {Function} called when all workers are disconnected and handlers are closed