关于中山市行政区域的问题和建议

当前 [L7中国地图数据](https://l7.antv.antgroup.com/custom/tools/map) 没有中山市下一级行政区域数据，中山市比较特别，没有区/县的划分，市的下一级行政区域是镇/街道。基于当前地图数据实现的省/市/区级联选择器只能选择市一级，而一般业务需要下探到中山市的镇/街道一级，我想问下这方面的数据是否考虑更新或者应该如何处理比较好？

Start with the L7 China map data tool linked in the issue and inspect how Zhongshan's administrative levels are represented. Determine whether town and street data can be added without the expected district level; done means the province/city/area selector can reach Zhongshan's towns and streets.

Written by the indexing model from the issue text.