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/ex_cmds.h b/src/ex_cmds.h
index 8f7c48f..ca7f292 100644
--- a/src/ex_cmds.h
+++ b/src/ex_cmds.h
@@ -552,8 +552,8 @@
 	EX_EXTRA|EX_NOTRLCOM|EX_EXPR_ARG|EX_SBOXOK|EX_CMDWIN|EX_LOCK_OK,
 	ADDR_NONE),
 EXCMD(CMD_echowindow,	"echowindow",	ex_execute,
-	EX_EXTRA|EX_NOTRLCOM|EX_EXPR_ARG|EX_SBOXOK|EX_CMDWIN|EX_LOCK_OK,
-	ADDR_NONE),
+	EX_RANGE|EX_EXTRA|EX_NOTRLCOM|EX_EXPR_ARG|EX_SBOXOK|EX_CMDWIN|EX_LOCK_OK,
+	ADDR_OTHER),
 EXCMD(CMD_else,		"else",		ex_else,
 	EX_TRLBAR|EX_SBOXOK|EX_CMDWIN|EX_LOCK_OK|EX_WHOLE,
 	ADDR_NONE),