Clarified git_repository_is_empty() documentation
diff --git a/include/git2/repository.h b/include/git2/repository.h
index 124aa67..2fb3813 100644
--- a/include/git2/repository.h
+++ b/include/git2/repository.h
@@ -342,8 +342,8 @@ GIT_EXTERN(int) git_repository_head_unborn(git_repository *repo);
/**
* Check if a repository is empty
*
- * An empty repository has just been initialized and contains
- * no references.
+ * An empty repository has just been initialized and contains no references
+ * apart from HEAD, which must be pointing to the unborn master branch.
*
* @param repo Repo to test
* @return 1 if the repository is empty, 0 if it isn't, error code