Clang: Add button to generate compile_commands.json

Change-Id: Iaabdcfc8d1b3463c3f6e5ce47536f9c52556eac0
Reviewed-by: Marco Bubke <marco.bubke@qt.io>

src/plugins/clangcodemodel/clangeditordocumentprocessor.cpp

@@ -475,7 +475,7 @@ private:
         }
 
         CppTools::CompilerOptionsBuilder builder(m_projectPart);
-        builder.addLanguageOption(fileKind);
+        builder.updateLanguageOption(fileKind);
 
         m_options.append(builder.options());
     }