title: type keyword and not analyzed, any difference?
body: <p>Is there any difference between the "<a href="https://www.elastic.co/guide/en/elasticsearch/reference/master/keyword.html" rel="noreferrer">keyword</a>" field type and a field that uses "<a href="https://www.elastic.co/guide/en/elasticsearch/guide/current/mapping-intro.html" rel="noreferrer">not_analyzed</a>" as analyzer in Elasticsearch? If there is one, when to use which?</p>