Make better recommendations for install of slow_exit in docstring.
Make better recommendations for install of slow_exit in docstring.

titeuf87/evennia,titeuf87/evennia,jamesbeebop/evennia,feend78/evennia,titeuf87/evennia,titeuf87/evennia,feend78/evennia,feend78/evennia,jamesbeebop/evennia,jamesbeebop/evennia,feend78/evennia