Make completion candidate match order configurable

[rolandwalker]

Description

While the default match order is very good, some users might choose to promote rapidfuzz approximate matches.

Future work: the hardcoded rapidfuzz thresholds should also be made tuneable.

Checklist

• I added this contribution to the changelog.md file.
• I added my name to the AUTHORS file (or it's already there).
• To lint and format the code, I ran

  uv run ruff check && uv run ruff format && uv run mypy --install-types .