Update docker provider networking docs from pull request feedback
Update docker provider networking docs from pull request feedback

mitchellh/vagrant,chrisroberts/vagrant,mitchellh/vagrant,bryson/vagrant,mitchellh/vagrant,sni/vagrant,marxarelli/vagrant,marxarelli/vagrant,marxarelli/vagrant,gitebra/vagrant,sni/vagrant,sni/vagrant,marxarelli/vagrant,gitebra/vagrant,chrisroberts/vagrant,gitebra/vagrant,bryson/vagrant,bryson/vagrant,chrisroberts/vagrant,chrisroberts/vagrant,gitebra/vagrant,sni/vagrant,bryson/vagrant,mitchellh/vagrant