Adding a minor grammatical correction. (#5388)

Proposing a minor grammatical correction on the useEffect API documentation page for triggering an animation example section.

beta/src/content/apis/react/useEffect.md

@@ -213,7 +213,7 @@ body {
 
 #### Triggering an animation {/*triggering-an-animation*/}
 
-In this example, the external system is the animation library in `animation.js`. It provides a JavaScript class called `FadeInAnimation` that takes a DOM node as an argument and exposes `start()` and `stop()` methods to control the animation. This component [uses a ref](/learn/manipulating-the-dom-with-refs) to access the underlying DOM node. The Effect reads the DOM node from the ref and automatically starts the animation for that node the component appears.
+In this example, the external system is the animation library in `animation.js`. It provides a JavaScript class called `FadeInAnimation` that takes a DOM node as an argument and exposes `start()` and `stop()` methods to control the animation. This component [uses a ref](/learn/manipulating-the-dom-with-refs) to access the underlying DOM node. The Effect reads the DOM node from the ref and automatically starts the animation for that node when the component appears.
 
 <Sandpack>