Span containing queryedit

Returns matches which enclose another span query. The span containing query maps to Lucene SpanContainingQuery. Here is an example:

GET /_search
{
  "query": {
    "span_containing": {
      "little": {
        "span_term": { "field1": "foo" }
      },
      "big": {
        "span_near": {
          "clauses": [
            { "span_term": { "field1": "bar" } },
            { "span_term": { "field1": "baz" } }
          ],
          "slop": 5,
          "in_order": true
        }
      }
    }
  }
}

The big and little clauses can be any span type query. Matching spans from big that contain matches from little are returned.