Merge bitcoindevkit/bdk#511: Fix nightly_docs.yml publish_docs 'Commit' step

947a9c29db7c7bb4855c84e70d986b9ab61339d6 Fix nightly_docs.yml publish_docs 'Commit' step (Steve Myers)

Pull request description:

  ### Description

  I forgot to fix in #503 the `nightly_docs.yaml` `publish_docs` `Commit` step to add new files for the path `./docs/.vuepress/public/docs-rs`.

  ### Checklists

  #### All Submissions:

  * [x] I've signed all my commits
  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)

ACKs for top commit:
  afilini:
    ACK 947a9c2

Tree-SHA512: d2bdbcb6cea46ec1949eba6f334acd5dbbe9b4b1323bb4713dc5d7f749666260ab05c29247c35f08c587b46d6bfb765c6a612c6522fd15211c84f7590f8c4748