style: fix 75 issues in additive_functionals

- admon: 4 fixes
- code: 6 fixes
- jax: 2 fixes
- link: 5 fixes
- math: 8 fixes
- ref: 3 fixes
- writing: 47 fixes

Rules addressed:
- qe-code-002: Use Unicode symbols for Greek letters in code
- qe-code-002: Use Unicode symbols for Greek letters in code
- qe-code-002: Use Unicode symbols for Greek letters in code
- qe-code-002: Use Unicode symbols for Greek letters in code
- qe-code-002: Use Unicode symbols for Greek letters in code
- qe-code-002: Use Unicode symbols for Greek letters in code
- qe-math-001: Prefer UTF-8 unicode for simple parameter mentions, be consistent
- qe-math-001: Prefer UTF-8 unicode for simple parameter mentions, be consistent
- qe-math-001: Prefer UTF-8 unicode for simple parameter mentions, be consistent
- qe-math-001: Prefer UTF-8 unicode for simple parameter mentions, be consistent
- ... and 65 more

Author: github-actions[bot]