patch 9.0.0683: cannot specify a time for :echowindow

Problem:    Cannot specify a time for :echowindow.
Solution:   A count can be used to specify the display time. Add
            popup_findecho().
diff --git a/src/vim9execute.c b/src/vim9execute.c
index df18f9e..c907360 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -3269,7 +3269,7 @@
 	    case ISN_ECHOCONSOLE:
 	    case ISN_ECHOERR:
 		{
-		    int		count = iptr->isn_arg.number;
+		    int		count;
 		    garray_T	ga;
 		    char_u	buf[NUMBUFLEN];
 		    char_u	*p;
@@ -3277,6 +3277,10 @@
 		    int		failed = FALSE;
 		    int		idx;
 
+		    if (iptr->isn_type == ISN_ECHOWINDOW)
+			count = iptr->isn_arg.echowin.ewin_count;
+		    else
+			count = iptr->isn_arg.number;
 		    ga_init2(&ga, 1, 80);
 		    for (idx = 0; idx < count; ++idx)
 		    {
@@ -3339,7 +3343,8 @@
 #ifdef HAS_MESSAGE_WINDOW
 			    else if (iptr->isn_type == ISN_ECHOWINDOW)
 			    {
-				start_echowindow();
+				start_echowindow(
+					      iptr->isn_arg.echowin.ewin_time);
 				msg_attr(ga.ga_data, echo_attr);
 				end_echowindow();
 			    }
@@ -6094,8 +6099,13 @@
 					  (varnumber_T)(iptr->isn_arg.number));
 		break;
 	    case ISN_ECHOWINDOW:
-		smsg("%s%4d ECHOWINDOW %lld", pfx, current,
-					  (varnumber_T)(iptr->isn_arg.number));
+		if (iptr->isn_arg.echowin.ewin_time > 0)
+		    smsg("%s%4d ECHOWINDOW %d (%ld sec)", pfx, current,
+				      iptr->isn_arg.echowin.ewin_count,
+				      iptr->isn_arg.echowin.ewin_time);
+		else
+		    smsg("%s%4d ECHOWINDOW %d", pfx, current,
+					     iptr->isn_arg.echowin.ewin_count);
 		break;
 	    case ISN_ECHOCONSOLE:
 		smsg("%s%4d ECHOCONSOLE %lld", pfx, current,