git: fix an obsolete comment about a `.jj/` path
The path to the file that indicates the last export to git was changed
when we added support for multiple workspaces.
@@ -209,8 +209,8 @@ pub fn export_changes(
/// Reflect changes made in the Jujutsu repo since last export in the underlying
/// Git repo. If this is the first export, nothing will be exported. The
-/// exported state's operation ID is recorded in the repo (`.jj/
-/// git_export_operation_id`).
+/// exported state's operation ID is recorded in the repo
+/// (`.jj/repo/git_export_operation_id`).
pub fn export_refs(
repo: &Arc<ReadonlyRepo>,
git_repo: &git2::Repository,
