Fix typo in Fast Refresh documentation (#85352)

Small grammar fix for fast-refresh.mdx

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### What?

Small grammer update on page introduction.

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This makes the sentence more readable.

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Co-authored-by: JJ Kasper <[email protected]>

Author: codr

docs/03-architecture/fast-refresh.mdx

@@ -3,7 +3,7 @@ title: Fast Refresh
 description: Fast Refresh is a hot module reloading experience that gives you instantaneous feedback on edits made to your React components.
 ---
 
-Fast refresh is a React feature integrated into Next.js that allows you live reload the browser page while maintaining temporary client-side state when you save changes to a file. It's enabled by default in all Next.js applications on **9.4 or newer**. With Fast Refresh enabled, most edits should be visible within a second.
+Fast refresh is a React feature integrated into Next.js that allows you to live reload the browser page while maintaining temporary client-side state when you save changes to a file. It's enabled by default in all Next.js applications on **9.4 or newer**. With Fast Refresh enabled, most edits should be visible within a second.
 
 ## How It Works