decorate choice line instead of just the symbol

[ishigo974]

Describe the change

Make active_color decorate the whole line in multi_select instead of just the radio button.

Why are we doing this?

Improve readability.

Benefits

The list of selected items will be more readable, especially when the row is long and you want to be sure the selected item has a value written at the end of the choice string.

Drawbacks

Change of default behavior

Requirements

• Tests written & passing locally?
• Code style checked?
• Rebased with master branch?
• Documentation updated?
  => The documentation is already confusing, at it says The answer provided by the user is also highlighted with the active color
• Changelog updated?
  => How am I supposed to choose the version and date?
  This is the changelog I would write:

Setting an `active_color` to `multi_select` now highlights the choice line and not only its radio button