docs(common): add docs to StreamableFile options

packages/common/file-stream/interfaces/streamable-options.interface.ts

@@ -1,10 +1,22 @@
 /**
  * Options for `StreamableFile`
  *
+ * @see [Streaming files](https://docs.nestjs.com/techniques/streaming-files)
+ *
  * @publicApi
  */
 export interface StreamableFileOptions {
+  /**
+   * The value that will be used for the `Content-Type` response header.
+   * @default `"application/octet-stream"`
+   */
   type?: string;
+  /**
+   * The value that will be used for the `Content-Disposition` response header.
+   */
   disposition?: string;
+  /**
+   * The value that will be used for the `Content-Length` response header.
+   */
   length?: number;
 }