fix: update updating.txt doc for user_src_input bug I originally thought it was not worth documenting because the error case had no impact. But deployed copies of the trackers can be updated to reduce differences between deployed and distributed files.

License
=======

Roundup is Free Software under the following license (from the
file COPYING.txt in the software distribution):

.. raw:: html

   <div class="file_insert">

.. include:: ../COPYING.txt

.. raw:: html

   </div>