Fixed #22748 -- Corrected post_migrate usage example.

Thanks Rudolph for the report.
Fixed #11776 -- Added CSS class for non-field/top of form errors.

Thanks Daniel Pope for the suggestion.
Fixed #22753 -- Documented ability to use a note with the {% comment %} tag.
Unicode method on model should return unicode

The example of a __unicode__ model method should return a unicode value
instead of a string.
Fixed #22384 -- Deprecated reversing URLs by dotted path.
Merge pull request #2756 from tubaman/return_unicode

Unicode method on model should return unicode
Removed erroneous trailing comma in OLMapWidget.js.
Updated current state of MySQL Connector/Python.