Quick Accent: add own accented letters and edit the existing ones

[watchmakerful]

Description of the new feature / enhancement

Ability to add, edit or reorder the accented characters in a text configuration file (or directly in the Settings form).

Scenario when this would be used?

Frequent usage of custom characters like ð, φ or π (especially as math symbols), or unusual diacritics like ę or ő.

Supporting information

No response