Merge pull request #3885 from Lakedaemon/shareWarningAndTwoMethods

Share warning and two methods

src/idl_gen_cpp.cpp

@@ -747,9 +747,7 @@ class CppGenerator : public BaseGenerator {
     if (IsEverythingGenerated()) return true;
 
     std::string code;
-    code =
-        "// automatically generated by the FlatBuffers compiler,"
-        " do not modify\n\n";
+    code = code + "// " + FlatBuffersGeneratedWarning();
 
     // Generate include guard.
     std::string include_guard_ident = file_name_;