spelling: runtime

(cherry picked from commit 386b4ae)

Author: jsoref

docs/rabbitmqctl.8

@@ -255,7 +255,7 @@ For example, to instruct the RabbitMQ node to terminate:
 .Dl rabbitmqctl stop
 .\" ------------------------------------
 .It Cm stop_app
-Stops the RabbitMQ application, leaving the runtme (Erlang VM) running.
+Stops the RabbitMQ application, leaving the runtime (Erlang VM) running.
 .Pp
 This command is typically run prior to performing other management
 actions that require the RabbitMQ application to be stopped, e.g.\&