chore: re-enable sphinx-toolbox

[tigarmo]

Upstream workflow has been bumped to use Python 3.10, so we can remove our bespoke initialisation of "every sphinx-toolbox extension except autonamedtuple".

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[codecov[bot]]

Codecov Report

Merging #198 (8cae550) into main (39473bb) will decrease coverage by 1.60%. The diff coverage is n/a.

:exclamation: Current head 8cae550 differs from pull request most recent head bb1d53b. Consider uploading reports for the commit bb1d53b to get more accurate results

@@            Coverage Diff             @@
##             main     #198      +/-   ##
==========================================
- Coverage   94.73%   93.13%   -1.60%     
==========================================
  Files           7        7              
  Lines        1063     1063              
  Branches      194      194              
==========================================
- Hits         1007      990      -17     
- Misses         53       66      +13     
- Partials        3        7       +4     

see 1 file with indirect coverage changes