docs(heatmap): 热力图补充密度热力图🇭说明：color、style callback 以及 state 不可用 (#2718)

Author: visiky

docs/api/plots/heatmap.en.md

@@ -25,7 +25,7 @@ Configure the data source. The data source is a collection of objects. For examp
 
 <description>**optional** _polygon | density_ _default:_ `polygon`</description>
 
-The density heat map needs to be specified as Density.
+The Density Heatmap needs to be specified as Density. Attention：Because of the particularity of Density Heatmap，Conditional color mapping is not supported. So when config `type='desity'`, `color callback`, `heatmapStyle` and style of `state` are not available.
 
 #### colorField
 

docs/api/plots/heatmap.zh.md

@@ -25,7 +25,7 @@ order: 23
 
 <description>**可选** _polygon | density_ _default:_ `polygon`</description>
 
-密度热力图需要指定为 density。
+密度热力图需要指定为 density。注意：由于密度热力图的特殊性，颜色配置不支持条件映射，因此当 `type='desity'` 时，color、heatmapStyle 回调不可用，state 状态样式也不可用。
 
 #### colorField