SDL_SYSLOADSO.c: Correct spelling mistake

publically -> publicly

src/loadso/windows/SDL_sysloadso.c

@@ -41,7 +41,7 @@ SDL_LoadObject(const char *sofile)
     }
     tstr = WIN_UTF8ToString(sofile);
 #ifdef __WINRT__
-    /* WinRT only publically supports LoadPackagedLibrary() for loading .dll
+    /* WinRT only publicly supports LoadPackagedLibrary() for loading .dll
        files.  LoadLibrary() is a private API, and not available for apps
        (that can be published to MS' Windows Store.)
     */