fix #29901: cursor left in note input mode

See issue report.  My expectations are simple: in note input mode, "C D" enters two notes and puts input cursor on the following rest (or whatever); I expect "left" to move it back to the note just entered, not back to the note *before* the one just entered.  This has bugged me forever.  Hopefully i'm not the only one.  Try this out if you like; I think you'll like it.