Added some links in i18n documentation

    class MyThing(models.Model):

        name = models.CharField(help_text=_('This is the help text'))

You can mark names of ``ForeignKey``, ``ManyToManyField`` or ``OneToOneField``

relationship as translatable by using their ``verbose_name`` options::

You can mark names of :class:`~django.db.models.ForeignKey`,

:class:`~django.db.models.ManyToManyField` or

:class:`~django.db.models.OneToOneField` relationship as translatable by using

their :attr:`~django.db.models.Options.verbose_name` options::

    class MyThing(models.Model):

        kind = models.ForeignKey(ThingKind, related_name='kinds',