Add support for scroll bar 'always' setting

[sotteson1]

This is for a PR that I'm submitting in the Terminal repo.

[opbld33]

Docs Build status updates of commit 145c9b8:

:white_check_mark: Validation status: passed

File	Status	Preview URL	Details
TerminalDocs/customize-settings/profile-appearance.md	:white_check_mark:Succeeded	View

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[nguyen-dows]

Thanks for writing this @sotteson1 👍