Input history adding an item that is a dupe should put it at the top of the stack too

[rchiodo]

Terminal window behaves this way. We didn't implement it this way.

Situation:

• Enter like 40 things into the input prompt
• On item 41 happen to enter something already typed
• Hit up to enter it again

Expected:
Last item typed is the first

Actual:
You have to go up through the list until you find it again.