Support for sphinx-build v1.6.7 and v1.8.5 broken (v9.18 and v9.19)

Warning, treated as error:
../../bin/dnssec/dnssec-importkey.rst:102:Duplicate explicit target name: "cmdoption-dnssec-importkey-P".

because of dnssec-importkey.rst having:

.. option:: -P date/offset
[...]
.. option:: -P sync date/offset

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information