(<MICRO SIGN>): Use `<-compat/unit' instead of `->decomposition' for

(<MICRO SIGN>): Use `<-compat/unit' instead of `->decomposition' for
<GREEK SMALL LETTER MU>.
- Use `<-noBreak' instead of `->decomposition' for compatibility
  mapping to single character tagged `noBreak'.
- Use `=>decomposition@compat' instead of `->decomposition' for
  compatibility decomposition mapping.
- Use `<-superscript' instead of `->decomposition' for compatibility
  mapping to single character tagged `super'.
- Add some auto-generated `<-canonical' features.
- Use `=>decomposition@fraction' instead of `->decomposition' for
  compatibility decomposition mapping tagged `fraction'.
- Use `=decomposition' instead of `->decomposition'.