use more true & false constants

src/mauville_old_man.c

@@ -445,7 +445,7 @@ static void DisableTextPrinters(struct TextPrinterTemplate * printer, u16 a1)
 
 static void DrawSongTextWindow(const u8 * str)
 {
-    DrawDialogueFrame(0, 0);
+    DrawDialogueFrame(0, FALSE);
     AddTextPrinterParameterized(0, FONT_NORMAL, str, 0, 1, 1, DisableTextPrinters);
     gDisableTextPrinters = TRUE;
     CopyWindowToVram(0, COPYWIN_FULL);