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/hardcopy.c b/src/hardcopy.c
index 508cf41..45800a1 100644
--- a/src/hardcopy.c
+++ b/src/hardcopy.c
@@ -657,7 +657,7 @@
 	bytes_to_print += (long_u)STRLEN(skipwhite(ml_get(lnum)));
     if (bytes_to_print == 0)
     {
-	MSG(_("No text to be printed"));
+	msg(_("No text to be printed"));
 	goto print_fail_no_begin;
     }