[Request] Show instructions for `multiselect` and `groupMultiselect`

[bluwy]

Is your feature request related to a problem? Please describe.
We had reports that it's unclear how to select items (changesets/changesets#255)

Describe the solution you'd like
It'd be nice to show instructions for selecting for multiselect and groupMultiselect, similar to autocomplete and autocompleteMultiselect today:

Maybe this could be under an option whether to show by default.

Describe alternatives you've considered
#551 is a similar issue of a more general footer option instead of like an instructions: boolean option

Additional context
n/a

[43081j]

makes sense to me 👍

to avoid a breaking change, i agree we need an option defaulted to off

[florian-lefebvre]

Would that really be breaking? I don't think it'd change the public API

[43081j]

@florian-lefebvre any CLI that has tests relying on snapshots, for example.

its not to do with the public API, its to do with the fact we changed how rendering works (which tests may be asserting against).

its probably not many though, so i could possibly be swayed to just include it and not have an option 🤔