patch 8.0.0724: the message for yanking doesn't indicate the register

Problem:    The message for yanking doesn't indicate the register.
Solution:   Show the register name in the "N lines yanked" message. (Lemonboy,
            closes #1803, closes #1809)
diff --git a/src/ops.c b/src/ops.c
index 2aec5d4..05ccc81 100644
--- a/src/ops.c
+++ b/src/ops.c
@@ -3167,19 +3167,29 @@
 	/* Some versions of Vi use ">=" here, some don't...  */
 	if (yanklines > p_report)
 	{
+	    char namebuf[100];
+
+	    if (oap->regname == NUL)
+		*namebuf = NUL;
+	    else
+		vim_snprintf(namebuf, sizeof(namebuf),
+						   " into \"%c", oap->regname);
+
 	    /* redisplay now, so message is not deleted */
 	    update_topline_redraw();
 	    if (yanklines == 1)
 	    {
 		if (oap->block_mode)
-		    MSG(_("block of 1 line yanked"));
+		    smsg((char_u *)_("block of 1 line yanked%s"), namebuf);
 		else
-		    MSG(_("1 line yanked"));
+		    smsg((char_u *)_("1 line yanked%s"), namebuf);
 	    }
 	    else if (oap->block_mode)
-		smsg((char_u *)_("block of %ld lines yanked"), yanklines);
+		smsg((char_u *)_("block of %ld lines yanked%s"),
+		     yanklines, namebuf);
 	    else
-		smsg((char_u *)_("%ld lines yanked"), yanklines);
+		smsg((char_u *)_("%ld lines yanked%s"), yanklines,
+		     namebuf);
 	}
     }