A small but easy optimization for `evaluate_repl()`: clone
`engine_state` 1x instead of 3x.
This reduces time spent in a simple REPL eval (`enter` key pressed with
no command text) by about 10%, as measured in
[Superluminal](https://superluminal.eu/).
At the moment `crossterm` apparently has a regression decoding certain important key combinations on Windows.
Thus reedline reverted to the previous version.
Some changes are necessary to remove the need for `crossterm` in the use of `lscolors`.
Introduces two local conversion traits.
Additionally update the `Highlighter` API to support the cursor
position.
This will enable brace/statement match highlighting.
