fix: remove useless content (#6615)

Author: loveloki

src/content/reference/react-dom/preinit.md

@@ -48,7 +48,7 @@ The `preinit` function provides the browser with a hint that it should start dow
 * `options`: an object. It contains the following properties:
   *  `as`: a required string. The type of resource. Its possible values are `script` and `style`.
   * `precedence`: a string. Required with stylesheets. Says where to insert the stylesheet relative to others. Stylesheets with higher precedence can override those with lower precedence. The possible values are `reset`, `low`, `medium`, `high`. 
-  *  `crossOrigin`: a string. The [CORS policy](https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/crossorigin) to use. Its possible values are `anonymous` and `use-credentials`. It is required when `as` is set to `"fetch"`.
+  *  `crossOrigin`: a string. The [CORS policy](https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/crossorigin) to use. Its possible values are `anonymous` and `use-credentials`.
   *  `integrity`: a string. A cryptographic hash of the resource, to [verify its authenticity](https://developer.mozilla.org/en-US/docs/Web/Security/Subresource_Integrity).
   *  `nonce`: a string. A cryptographic [nonce to allow the resource](https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/nonce) when using a strict Content Security Policy. 
   *  `fetchPriority`: a string. Suggests a relative priority for fetching the resource. The possible values are `auto` (the default), `high`, and `low`.