message: Updated the roadmap for U command.
diff: @@ -486,7 +486,7 @@ Status | Command | Description | Note
  ---|--------|-------|------------------------------
  :white_check_mark: | :1234: u | undo last N changes | Current implementation may not cover every case perfectly.
  :white_check_mark: | :1234: CTRL-R | redo last N undone changes | As above.
  -:arrow_down: | U | restore last changed line
  +:white_check_mark: | U | restore last changed line
  ## External commands
  