Add separator params to Storage facade docblocks (#60703)

Author: Muhtasim-Munif-Fahim

src/Illuminate/Support/Facades/Storage.php

@@ -33,8 +33,8 @@
  * @method static bool writeStream(string $path, resource $resource, array $options = [])
  * @method static string getVisibility(string $path)
  * @method static bool setVisibility(string $path, string $visibility)
- * @method static bool prepend(string $path, string $data)
- * @method static bool append(string $path, string $data)
+ * @method static bool prepend(string $path, string $data, string $separator = PHP_EOL)
+ * @method static bool append(string $path, string $data, string $separator = PHP_EOL)
  * @method static bool delete(string|array $paths)
  * @method static bool copy(string $from, string $to)
  * @method static bool move(string $from, string $to)