Issue 7293 - Moved decorative prefix out of translatable strings
This MR for #334 (closed) contains the following changes:
- Removed "+" prefix from translatable strings.
- Added "+" character to font generation config.
- Add "+" prefix via CSS in mobile options page and desktop options page.
- Don't use CSS to add "+" prefix in
IOListBoxbecause we'll reuse no longer need the CSS style for the desktop options page after #129 (closed).