resolve all warnings from CI -- [2024-09-02]

[jGaboardi]

This PR:

• add a root-level conftest.py in order to skip doctests for _indices.py only
  • add root-level conftest.py to skip doctest only in _indices.py #82
• resolves all warnings in latest CI
  • adjust tests for warnings #81
• big drop in coverage due to not performing doctests in _indices.py anymore.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 62.7%. Comparing base (e82c306) to head (e6db5a4).
Report is 3 commits behind head on main.

❗ There is a different number of reports uploaded between BASE (e82c306) and HEAD (e6db5a4). Click for more details.

HEAD has 7 uploads less than BASE

Flag	BASE (e82c306)	HEAD (e6db5a4)
	14	7

Additional details and impacted files

@@           Coverage Diff            @@
##            main     #83      +/-   ##
========================================
- Coverage   96.7%   62.7%   -34.1%     
========================================
  Files          7       7              
  Lines        490     490              
========================================
- Hits         474     307     -167     
- Misses        16     183     +167     

Files with missing lines	Coverage Δ
inequality/pen.py	89.8% <100.0%> (ø)

... and 1 file with indirect coverage changes