Fix typo in example for `useFragment` docs
Summary: Pull Request resolved:
@@ -211,7 +211,7 @@ function App() {
### `useFragment`
```javascript
-import type {**UserComponent_user$key**} from 'UserComponent_user.graphql';
+import type {UserComponent_user$key} from 'UserComponent_user.graphql';
const React = require('React');
