Currently sagemath-categories distributes a superset of sagemath-objects, and both distributions include a copy of the doctester for their doctesting. We remove this duplication by declaring install-requires and extras-require.

The dependencies are illustrated in the updated developer's guide - https://e019add9a8540b8213dfc563e8e4bda04777282c--sagemath-tobias.netlify.app/developer/packaging_sage_library.html#hierarchy-of-distribution-packages

As #33817 is a dependency, this ticket can be tested by running

./bootstrap && make SAGE_CHECK=yes pypi-wheels

This test is also run as part of the "Build&Test" workflow.

CC: @kwankyu

Component: refactoring

Author: Matthias Koeppe

Branch/Commit: e5d1070

Reviewer: Kwankyu Lee

Issue created by migration from https://trac.sagemath.org/ticket/33812