patch 9.0.0318: clearing screen causes flicker

Problem:    Clearing screen causes flicker.
Solution:   Do not clear but redraw in more cases.  Add () to "wait_return".
diff --git a/src/misc1.c b/src/misc1.c
index e8216a0..8257f76 100644
--- a/src/misc1.c
+++ b/src/misc1.c
@@ -616,7 +616,7 @@
 
     while (r != 'y' && r != 'n')
     {
-	// same highlighting as for wait_return
+	// same highlighting as for wait_return()
 	smsg_attr(HL_ATTR(HLF_R), "%s (y/n)?", str);
 	if (direct)
 	    r = get_keystroke();