Captailize "Strict Mode" (#6426)

Summary of changes:
There is one "TypeScript strict mode" that is kept unchanged.

Co-authored-by: xuan.huang <[email protected]>

Author: Huxpro

src/content/reference/react/StrictMode.md

@@ -95,7 +95,7 @@ Strict Mode enables the following checks in development:
 
 ---
 
-### Enabling strict mode for a part of the app {/*enabling-strict-mode-for-a-part-of-the-app*/}
+### Enabling Strict Mode for a part of the app {/*enabling-strict-mode-for-a-part-of-the-app*/}
 
 You can also enable Strict Mode for any part of your application: