title: Rename a function used across a package
check: python -m pytest -q .bench_check
plan: |
  Milestone 1: rename `load_config` to `read_settings` across the project.

  1. Find every use of `load_config`: run
     `grep -rnw load_config --include=*.py --include=*.md .`
     It is defined in `shopkeeper/config.py` and used in many other modules,
     in tests, in docstrings, in comments, in a log message and in
     `README.md`.
  2. Rename the function to `read_settings` everywhere: its definition,
     imports, calls, `__all__`, docstrings, comments, strings and
     `README.md`. Afterwards the grep in step 1 must print nothing.
  3. Rename only that exact name. `load_config_defaults` and `reload_config`
     are different functions and keep their names. Change no behaviour.
  4. Update the tests under `tests/` to use the new name, and run
     `python -m pytest -q` until every test passes.
  5. Call finish_milestone, with final yes.