Revert "Don't mention exit_on_close at all in the examples"
Revert "Don't mention exit_on_close at all in the examples"

This reverts commit 665d5f89aeacce405152b43e823eb8040c379c71.

This needs an in depth discussion since. Our default happens
to be different from gen_tcp, Ranch doesn't force it and
RabbitMQ defaults where introduced in early 2011 when
socket listen options became configurable.

rabbitmq/rabbitmq-website,rabbitmq/rabbitmq-website,rabbitmq/rabbitmq-website,rabbitmq/rabbitmq-website,rabbitmq/rabbitmq-website