don't print flag name again

cmd/leagueflag.go

@@ -50,7 +50,7 @@ func (t *leagueFlag) Set(v string) error {
 	_, ok := leagueIDs[v]
 	if !ok {
 		allowed := keys(leagueIDs)
-		err = flagValueError("league", allowed)
+		err = flagValueError(allowed)
 	} else {
 		*t = leagueFlag(v)
 	}

cmd/sportflag.go

@@ -55,7 +55,7 @@ func (t *sportFlag) Set(v string) error {
 	_, ok := sportIDs[v]
 	if !ok {
 		allowed := keys(sportIDs)
-		err = flagValueError("sport", allowed)
+		err = flagValueError(allowed)
 	} else {
 		*t = sportFlag(v)
 	}

cmd/teamflag.go

@@ -68,10 +68,10 @@ func keys[V any](m map[string]V) []string {
 	return keys
 }
 
-func flagValueError(name string, allowed []string) error {
+func flagValueError(allowed []string) error {
 	sort.Strings(allowed)
 	allowedList := strings.Join(allowed, ", ")
-	return errors.New(name + " must be one of " + allowedList)
+	return errors.New("must be one of " + allowedList)
 }
 
 type teamFlag string
@@ -87,7 +87,7 @@ func (t *teamFlag) Set(v string) error {
 	_, ok := teamIDs[v]
 	if !ok {
 		allowed := keys(teamIDs)
-		err = flagValueError("team", allowed)
+		err = flagValueError(allowed)
 	} else {
 		*t = teamFlag(v)
 	}