Fixed #12516. Added the new location of email_re to the release notes. This...

Fixed #12516. Added the new location of email_re to the release notes. This regex is undocumented, so we're not putting in an import for backwards compatibility.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12213 bcc190cf-cafb-0310-a4f2-bffc1f526a37