patch 8.1.0779: argument for message functions is inconsistent

Problem:    Argument for message functions is inconsistent.
Solution:   Make first argument to msg() "char *".
diff --git a/src/window.c b/src/window.c
index f9b4999..792288f 100644
--- a/src/window.c
+++ b/src/window.c
@@ -310,7 +310,7 @@
 /* move window to new tab page */
     case 'T':
 		if (one_window())
-		    MSG(_(m_onlyone));
+		    msg(_(m_onlyone));
 		else
 		{
 		    tabpage_T	*oldtab = curtab;
@@ -3379,7 +3379,7 @@
     if (one_window())
     {
 	if (message && !autocmd_busy)
-	    MSG(_(m_onlyone));
+	    msg(_(m_onlyone));
 	return;
     }