python: Normalize quotes with Black.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

zerver/migrations/0048_enter_sends_default_to_false.py

@@ -5,13 +5,13 @@ from django.db import migrations, models
 class Migration(migrations.Migration):
 
     dependencies = [
-        ('zerver', '0047_realm_add_emoji_by_admins_only'),
+        ("zerver", "0047_realm_add_emoji_by_admins_only"),
     ]
 
     operations = [
         migrations.AlterField(
-            model_name='userprofile',
-            name='enter_sends',
+            model_name="userprofile",
+            name="enter_sends",
             field=models.NullBooleanField(default=False),
         ),
     ]