Allow % as chord symbol
GIT commit: dd4530e
See discussion in https://musescore.org/en/node/83781. The request is to allow "%" to be typed in a chord symbol and be automatically converted to the measure repeat sign.
This would be very easy in principle; just a matter of adding appropriate sym and/or token tags to the XML files. But an issue might be that most fonts won't include the measure repeat symbol, so we might have to special case this and force the musical text font to be used instead.