doc: add err param to fs.cp callback

PR-URL: #53234
Reviewed-By: LiviaMedeiros <livia@cirno.name>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

doc/api/fs.md

@@ -2399,6 +2399,7 @@ changes:
   * `verbatimSymlinks` {boolean} When `true`, path resolution for symlinks will
     be skipped. **Default:** `false`
 * `callback` {Function}
+  * `err` {Error}
 
 Asynchronously copies the entire directory structure from `src` to `dest`,
 including subdirectories and files.

lib/fs.js

@@ -3045,7 +3045,7 @@ function copyFileSync(src, dest, mode) {
  * @param {string | URL} src
  * @param {string | URL} dest
  * @param {object} [options]
- * @param {() => any} callback
+ * @param {(err?: Error) => any} callback
  * @returns {void}
  */
 function cp(src, dest, options, callback) {