Add docstring to revision param for downloadFile (#714)

Copies the docstring in the [Python
counterpart](https://huggingface.co/docs/huggingface_hub/v0.23.1/en/package_reference/hf_api#huggingface_hub.HfApi.hf_hub_download)

---------

Co-authored-by: Eliott C <[email protected]>

Author: jinnovation

packages/hub/src/lib/download-file.ts

@@ -16,6 +16,11 @@ export async function downloadFile(params: {
 	 * For example, when calling on a file stored with Git LFS, the pointer file will be downloaded instead.
 	 */
 	raw?: boolean;
+	/**
+	 * An optional Git revision id which can be a branch name, a tag, or a commit hash.
+	 *
+	 * @default "main"
+	 */
 	revision?: string;
 	/**
 	 * Fetch only a specific part of the file