Document that stopApp() may cause issues when running apps with multiple sessions connected

[pyltime]

If you are running an a Shiny app that has multiple sessions connected to it (say, because you're running it on Posit Connect or a similar environment), calling stopApp() will stop all user sessions. This is mentioned in the Community post here: https://forum.posit.co/t/shiny-app-disconnecting-when-using-stopapp-in-onsessionended/28213/2
but it would be great to mention this in the documentation for stopApp() itself so it's clear that this may cause problems depending on where and how the app is running.