Clean URLs description made user assume pathauto-like functionality.

Issue Link: 
http://drupal.org/node/392362
criticality: 
Minor
Drupal7: 
Open
Task: 
Install Drupal
This happened to: 
Participant 10
Participant 2
Participant 3
Participant 4
Participant 5
Participant 6
Participant 7
Participant 8

Because of the description of clean URLs the participant assumed there would be pathauto like functionality. This caused them some issues with the path field when trying to create a menu item link.

Additionally the description didn't really tell users what clean URLs are. Most users expressed confusion over what it meant, but stuck with the default anyway.

Solution: 
Who wouldn't want clean URLs? if available, we should just enable and hide the option on install. If not available, let them know their server doesn't support the feature currently, along with some compelling reasons to have a server that does.