Support RNA without root
1) Score with notes
2) Select a note
3) Add / Text / Roman Numeral Analysis
4) Type "64"
Result: no fancy stacking of the numbers - this only works after a root. Similarly, a leading hyphen or equals sign won't produce the formatting you'd get after an inversions. This came up on the forum. I've got a fix I'm working on in the font itself also requires a very slight tweak to MuseScore (we need to not strip out a leading "=" from RNA elements, which we do only because this code was inherited from chord symbols which use that internally to force a literal spelling).