fix: tweak Nomination.share_nominator label text (ietf-tools#5775)

* fix: tweak Nomination.share_nominator label text

"Share nominator name with candidate" was confusing, because it's
imperative, where it's really intended to be permissive - it's okay to
share with the candidate.

* chore: add migration for label text

ietf/nomcom/migrations/0003_alter_nomination_share_nominator.py

@@ -0,0 +1,21 @@
+# Generated by Django 4.2.2 on 2023-06-08 18:06
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("nomcom", "0002_add_uncheck_reminder"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="nomination",
+            name="share_nominator",
+            field=models.BooleanField(
+                default=False,
+                help_text="Check this box to allow the NomCom to let the person you are nominating know that you were one of the people who nominated them. If you do not check this box, your name will be confidential and known only within NomCom.",
+                verbose_name="OK to share nominator's name with candidate",
+            ),
+        ),
+    ]

ietf/nomcom/models.py

@@ -130,7 +130,7 @@ class Nomination(models.Model):
     nominator_email = models.EmailField(verbose_name='Nominator Email', blank=True)
     user = ForeignKey(User, editable=False, null=True, on_delete=models.SET_NULL)
     time = models.DateTimeField(auto_now_add=True)
-    share_nominator = models.BooleanField(verbose_name='Share nominator name with candidate', default=False,
+    share_nominator = models.BooleanField(verbose_name='OK to share nominator\'s name with candidate', default=False,
                                           help_text='Check this box to allow the NomCom to let the '
                                                     'person you are nominating know that you were '
                                                     'one of the people who nominated them. If you '