site: fix grammatical issue in tutorial/update (sveltejs#6136)

site/content/tutorial/07-lifecycle/03-update/text.md

@@ -2,7 +2,7 @@
 title: beforeUpdate and afterUpdate
 ---
 
-The `beforeUpdate` function schedules work to happen immediately before the DOM has been updated. `afterUpdate` is its counterpart, used for running code once the DOM is in sync with your data.
+The `beforeUpdate` function schedules work to happen immediately before the DOM is updated. `afterUpdate` is its counterpart, used for running code once the DOM is in sync with your data.
 
 Together, they're useful for doing things imperatively that are difficult to achieve in a purely state-driven way, like updating the scroll position of an element.
 
@@ -21,4 +21,4 @@ afterUpdate(() => {
 });
 ```
 
-Note that `beforeUpdate` will first run before the component has mounted, so we need to check for the existence of `div` before reading its properties.
+Note that `beforeUpdate` will first run before the component has mounted, so we need to check for the existence of `div` before reading its properties.