docs: def _sync_to_disk(self):
          """Write any changes made on Refpkg to disk.
  
          Other methods of Refpkg that alter the contents of the package
          will call this method themselves.  Generally you should never
          have to call it by hand.  The only exception would be if
          another program has changed the Refpkg on disk while your
          program is running and you want to force your version over it.
          Otherwise it should only be called by other methods of refpkg.
          """
          with self.open_manifest('w') as h:
              json.dump(self.contents, h, indent=4)
              h.write('\n')