pkg/form: fix bad locale reference (#5196)

pkg/form/repo.go

@@ -262,7 +262,7 @@ func (f *CreateMilestone) Validate(ctx *macaron.Context, errs binding.Errors) bi
 
 type CreateLabel struct {
 	ID    int64
-	Title string `binding:"Required;MaxSize(50)" locale:"repo.issues.label_name"`
+	Title string `binding:"Required;MaxSize(50)" locale:"repo.issues.label_title"`
 	Color string `binding:"Required;Size(7)" locale:"repo.issues.label_color"`
 }