doc: fix deprecated alias description in cluster

Refs: nodejs#36478

PR-URL: nodejs#41618
Reviewed-By: Mestery <[email protected]>
Reviewed-By: Antoine du Hamel <[email protected]>
Reviewed-By: Mohammed Keyvanzadeh <[email protected]>
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>

Author: tniessen

doc/api/cluster.md

@@ -855,7 +855,6 @@ deprecated: v16.0.0
 -->
 
 Deprecated alias for [`cluster.isPrimary`][].
-details.
 
 ## `cluster.isPrimary`