Fix grammar in Popup.md: "subtle then checkout" → "subtle, then check out" (#628)

* Initial plan

* Fix typo: add comma after "subtle" and change "checkout" to "check out"

Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com>

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com>

Author: Copilot

docs/maui/views/Popup.md

@@ -10,7 +10,7 @@ ms.date: 04/12/2022
 Popups are a common way of presenting information to a user that relates to their current task. Operating systems provide a way to show a message and require a response from the user, these alerts are typically restrictive in terms of the content a developer can provide and also the layout and appearance.
 
 > [!NOTE]
-> If you wish to present something to the user that is more subtle then checkout our [Toast](../alerts/toast.md) and [Snackbar](../alerts/snackbar.md) options.
+> If you wish to present something to the user that is more subtle, then check out our [Toast](../alerts/toast.md) and [Snackbar](../alerts/snackbar.md) options.
 
 The `Popup` view allows developers to build their own custom UI and present it to their users.