Refresh search analyzer

With ISM installed, you can refresh search analyzers in real time with the following API:

POST /_opendistro/_refresh_search_analyzers/<index or alias or wildcard>

For example, if you change the synonym list in your analyzer, the change takes effect without you needing to close and reopen the index.

To work, the token filter must have an updateable flag of true:

{
  "analyzer": {
    "my_synonyms": {
      "tokenizer": "whitespace",
      "filter": [
        "synonym"
      ]
    }
  },
  "filter": {
    "synonym": {
      "type": "synonym_graph",
      "synonyms_path": "synonyms.txt",
      "updateable": true
    }
  }
}