Fix typo

[MisinformedDNA]

What changes to the docs does this PR provide?

Fixes type

PR Checklist

Please check if your PR fulfills the following requirements:

• [X ] Correctly picked the right branch to base the change off (dev for new features, master for typos/improvements)
• [X ] For new pages, used the provided template
• [X ] For new features, added an entry in the Table of Contents
• [X ] Ran against a spell and grammar checker
• [X ] Contains NO breaking changes

[opbld31]

Docs Build status updates of commit dc7d0ae:

:white_check_mark: Validation status: passed

File	Status	Preview URL	Details
docs/mvvm/ObservableRecipient.md	:white_check_mark:Succeeded	View

For more details, please refer to the build report.

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