Improve consistency of help text for slack

opentech/apply/users/forms.py

@@ -39,7 +39,7 @@ class ProfileForm(forms.ModelForm):
         if slack:
             slack = slack.strip()
             if ' ' in slack:
-                raise forms.ValidationError('Slack IDs must not include spaces')
+                raise forms.ValidationError('Slack names must not include spaces')
 
             if not slack.startswith('@'):
                 slack = '@' + slack

opentech/apply/users/migrations/0007_user_slack.py

@@ -13,6 +13,6 @@ class Migration(migrations.Migration):
         migrations.AddField(
             model_name='user',
             name='slack',
-            field=models.CharField(blank=True, help_text='This is the name we should "@" when sending notifications', max_length=50, verbose_name='Slack name'),
+            field=models.CharField(blank=True, help_text='This is the name we should "@mention" when sending notifications', max_length=50, verbose_name='Slack name'),
         ),
     ]

opentech/apply/users/models.py

@@ -59,7 +59,7 @@ class User(AbstractUser):
     slack = models.CharField(
         verbose_name='Slack name',
         blank=True,
-        help_text='This is the name we should "@" when sending notifications',
+        help_text='This is the name we should "@mention" when sending notifications',
         max_length=50,
     )