Fixed grammatical error

Fixes grammatical error in `Buttons that only show up on hover`

data.json

@@ -46,7 +46,7 @@
   {
     "name": "buttons-that-only-show-up-on-hover",
     "shortTip": "Buttons that only show up on hover",
-    "longTip": "Be mindful of a pattern where buttons are hidden and only get displayed when parent element is hovered: this can make the buttons inaccessible from keyboard. instead us using `display:none` or `visibility: hidden`, consider using alternative methods, e.g. using `position: absolute` and pushing it off the screen.\n\n",
+    "longTip": "Be mindful of a pattern where buttons are hidden and only get displayed when parent element is hovered: this can make the buttons inaccessible from keyboard. instead of using `display:none` or `visibility: hidden`, consider using alternative methods, e.g. using `position: absolute` and pushing it off the screen.\n\n",
     "links": [
       "[See how angular hides elements with cdk-visually-hidden class](https://cs.corp.google.com/piper///depot/google3/third_party/javascript/angular2_material/src/cdk/a11y/_a11y.scss)"
     ],
@@ -201,4 +201,4 @@
     "category": "pro tip",
     "categoryId": 1
   }
-]
+]