delete agora in cpp map

Author: Suri539

dita/RTC-NG/RTC_NG_API_CPP.ditamap

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE map PUBLIC "-//OASIS//DTD DITA Map//EN" "map.dtd">
 <map>
-    <title>Agora C++ API Reference for All Platforms</title>
+    <title>C++ API Reference for All Platforms</title>
     <topicmeta>
         <navtitle>C++ API Reference</navtitle>
     </topicmeta>