fix: add eof

Author: hg-pyun

src/content/reference/eslint-plugin-react-hooks/lints/error-boundaries.md

@@ -70,4 +70,4 @@ function App() {
   );
 }
 
-```
+```

src/content/reference/eslint-plugin-react-hooks/lints/immutability.md

@@ -159,4 +159,4 @@ function UserProfile() {
   };
 }
 
-```
+```