Add I18N comment

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@7444 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/states_screens/race_gui.cpp

@@ -1113,6 +1113,7 @@ void RaceGUI::drawGlobalMusicDescription()
     core::stringw thetext_composer;
     if (mi->getComposer()!="")
     {
+        // I18N: string used to show the author of the music. (e.g. "Sunny Song" by "John Doe")
         thetext_composer = _("by");
         thetext_composer += " ";
         thetext_composer += mi->getComposer().c_str();