pinyin搜索，怎么高亮显示对应中文 7.9.3版本

[xiaohoutongxue]

mapping:
{
"article" : {
"mappings" : {
"properties" : {
"_class" : {
"type" : "text",
"fields" : {
"keyword" : {
"type" : "keyword",
"ignore_above" : 256
}
}
},
"content" : {
"type" : "text",
"fields" : {
"pinyin" : {
"type" : "text",
"analyzer" : "pinyin"
}
},
"analyzer" : "ik_max_word"
},
"createTime" : {
"type" : "long"
},
"title" : {
"type" : "text",
"fields" : {
"pinyin" : {
"type" : "text",
"analyzer" : "pinyin"
}
},
"analyzer" : "ik_max_word"
}
}
}
}
}

搜索
GET /article/_search
{
"query":{
"multi_match": {
"query": "shenshang",
"fields": ["content.pinyin"]
}
},
"highlight": {
"pre_tags" : [""],
"post_tags" : [""],
"fields": {
"content.pinyin": {}
}
}
}

结果：
"highlight" : {
"content.pinyin" : [
"迪斯科浪费空间四点零分了是对方身上的"
]
}

怎么让这个pre_tags 打在 对应拼音的汉字上呢