Updated Usage (markdown)

Usage.md

@@ -175,6 +175,7 @@ optional args:
  -S      persistent session
  -t secs timeout to lock
  -T key  sort order [a/d/e/r/s/t/v]
+ -u      use selection (no prompt)
  -U      show user and group
  -V      show version
  -w      place HW cursor on hovered