Terminal suggest absolute path support

[Tyriar]

Fixes #237979

TODO:

• Merge Support CDPATH in terminal suggest #239406 first
• Test on mac

Deferring C|, C:|, :| support as it's more complicated than I initially thought:

• The drives should be consistently returned for any folder request without a slash, this could get annoying when using if you're just cding into a local dir and c: is a suggestion.
• Would : need to be a trigger char on Windows only?
• This depends on return files/folder completions unless specific options / args are provided #239384 which isn't merged yet
• Because of the above we may not want to do it at all?

[Tyriar]

@meganrogge hold off reviewing until #239406 is in.

The merge-base changed after approval.