Update hover-focus-and-other-states.mdx (tailwindlabs#1480)

Author: decaylala

src/pages/docs/hover-focus-and-other-states.mdx

@@ -1690,7 +1690,7 @@ Style an element when the user hovers over it with the mouse cursor using the `h
 
 #### focus <small>(:focus)</small>
 
-Style an element when it has focus the `focus` modifier:
+Style an element when it has focus using the `focus` modifier:
 
 ```html
 <input class="border-gray-300 **focus:border-blue-400** ..." />