ledger-mode: Remove duplication in ledger-set-{year,month}
ledger-mode: Remove duplication in ledger-set-{year,month}

afh/ledger,jwakely/ledger,afh/ledger,afh/ledger,jwakely/ledger,ledger/ledger,duncanmortimer/ledger,afh/ledger,duncanmortimer/ledger,paulbdavis/ledger,jwakely/ledger,jwakely/ledger,paulbdavis/ledger,duncanmortimer/ledger,jwakely/ledger,ledger/ledger,duncanmortimer/ledger,paulbdavis/ledger,duncanmortimer/ledger,paulbdavis/ledger,paulbdavis/ledger,jwakely/ledger,ledger/ledger,paulbdavis/ledger,jwakely/ledger,duncanmortimer/ledger,paulbdavis/ledger,ledger/ledger,duncanmortimer/ledger,afh/ledger,ledger/ledger