Fix type name and add some info

[wcruz-br]

• Fixed type from matchProfile to matchProfiles
• Added a note about using source as property for matching (after wasting about an hour trying to make it work...)

[learn-build-service-prod[bot]]

Learn Build status updates of commit 453d2ad:

:white_check_mark: Validation status: passed

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

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[mattwojo]

Thank you @wcruz-br! Appreciate the catch and the fix! Merged.