add help text for date fields

catalog/game/models.py

@@ -102,6 +102,7 @@ class Game(Item):
         auto_now_add=False,
         null=True,
         blank=True,
+        help_text=_("YYYY-MM-DD"),
     )
 
     genre = jsondata.ArrayField(

catalog/music/models.py

@@ -55,7 +55,9 @@ class Album(Item):
         "duration",
         "bandcamp_album_id",
     ]
-    release_date = jsondata.DateField(_("发行日期"), null=True, blank=True)
+    release_date = jsondata.DateField(
+        _("发行日期"), null=True, blank=True, help_text=_("YYYY-MM-DD")
+    )
     duration = jsondata.IntegerField(_("时长"), null=True, blank=True, help_text=_("毫秒数"))
     artist = jsondata.ArrayField(
         models.CharField(blank=True, default="", max_length=200),