在代码块加入识别C++代码

增加输入CPP代码时, 代码块右上角的语言显示为C++

source/less/_article.less

@@ -498,6 +498,9 @@
   &.c .code:before{
       content: "C";
   }
+  &.cpp .code:before{
+      content: "C++";
+  }
   &.java .code:before{
       content: "JAVA";
   }