Update text-decoration.md

docs/uni-app-x/css/text-decoration.md

@@ -9,4 +9,7 @@
 
 <!-- CSSJSON.text-decoration.compatibility -->
 
-<!-- CSSJSON.text-decoration.reference -->
\ No newline at end of file
+#### App平台差异  
+text-decoration 样式不支持继承，仅对 [text](uni-app-x/component/text.md) 组件生效。  
+
+<!-- CSSJSON.text-decoration.reference -->