Use unicode DOT OPERATOR instead of MIDDLE DOT in pretty printing

[rikardn]

• Closes Pretty printing using MIDDLE DOT unicode character instead of DOT OPERATOR #2272
• Executed pre-commit run --all-files or pixi run lint --all-files with no errors
• The change is fully covered by automated unit tests
• Documented in docs/ as appropriate
• Added an entry to the CHANGES file

I replaced all instances o the DOT OPERATOR character with MIDDLE DOT in code, documentation and tests.