open fun unregisterCommand(commandName: String): CommandRegistry
Like io.vertx.reactivex.ext.shell.command.CommandRegistry#unregisterCommand, without a completion handler.
Return
open fun unregisterCommand(commandName: String, completionHandler: Handler<AsyncResult<Void>>): CommandRegistry
Unregister a command.
commandName - the command name
completionHandler - notified when the command is unregistered
Return
a reference to this, so the API can be used fluently