fix(社区): 修复@xx字符被意外截断问题 reviewed by tao.huang

@@ -81,7 +81,7 @@ export default {
         }
 
         if (line > this.maxLines) {
-          textArr[this.maxLines] = textArr[this.maxLines].substring(0, Math.min(17, textArr[this.maxLines].length));
+          textArr[this.maxLines] = textArr[this.maxLines].substring(0, Math.max(17, textArr[this.maxLines].length));
           return false;
         }
       });