BUG

Description

• Sort->toArray() always generate 'missing' key in result.
• https://github.com/Spameri/ElasticQuery/blob/master/src/Options/Sort.php

• ElasticQuery/src/Options/Sort.php

  Lines 62 to 68 in 04295e5

  	public function toArray() : array
  	{
  	return [
  	$this->field => [
  	'order' => $this->type,
  	'missing' => $this->missing,
  	],

(new Sort('_score'))->toArray()

ES error

{
  "error" : {
    "root_cause" : [
      {
        "type" : "x_content_parse_exception",
        "reason" : "[14:9] [_score] unknown field [missing]"
      }
    ],
    "type" : "x_content_parse_exception",
    "reason" : "[14:9] [_score] unknown field [missing]"
  },
  "status" : 400
}