Update overview.md

[the-wazz]

tiny grammar fix. hyphen added.

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

Learn Build status updates of commit fea1d22:

:white_check_mark: Validation status: passed

File	Status	Preview URL	Details
msix-src/overview.md	:white_check_mark:Succeeded

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel