Fix for bug b)

- Don't attempt to save if there are duplicates
- Fix overwritten variable name
- Provide correct return data to the form

InvenTree/stock/migrations/0020_auto_20200206_1213.py

@@ -0,0 +1,19 @@
+# Generated by Django 2.2.9 on 2020-02-06 12:13
+
+from django.db import migrations
+import markdownx.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0019_auto_20200202_1024'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='stockitem',
+            name='notes',
+            field=markdownx.models.MarkdownxField(blank=True, help_text='Stock Item Notes', null=True),
+        ),
+    ]