es-settings.json

{
  "index": {
    "analysis": {
      "filter": {
        "autocomplete_filter": {
          "type": "edge_ngram",
          "min_gram": "1",
          "max_gram": "20"
        },
        "word_joiner": {
          "type": "word_delimiter",
          "catenate_all": true
        }
      },
      "analyzer": {
        "autocomplete": {
          "type": "custom",
          "filter": [
            "lowercase",
            "word_joiner",
            "autocomplete_filter"
          ],
          "tokenizer": "keyword"
        },
        "keyword_lowercase": {
          "filter": "lowercase",
          "type": "custom",
          "tokenizer": "keyword"
        },
        "default": {
          "type": "snowball"
        }
      }
    }
  }
}

Produces the following:

» curl -s -XGET 'localhost:9200/test/_analyze?analyzer=autocomplete&pretty=1' -d 'Pizza Hut' | jq ".tokens[]|.token" -r
p
pi
piz
pizz
pizza
p
pi
piz
pizz
pizza
pizzah
pizzahu
pizzahut
h
hu
hut