patch 8.1.1446: popup window callback not implemented yet

Problem:    Popup window callback not implemented yet.
Solution:   Implement the callback.
diff --git a/src/evalfunc.c b/src/evalfunc.c
index ccb8b3e..bc60567 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -810,7 +810,7 @@
 #endif
 #ifdef FEAT_TEXT_PROP
     {"popup_atcursor",	2, 2, f_popup_atcursor},
-    {"popup_close",	1, 1, f_popup_close},
+    {"popup_close",	1, 2, f_popup_close},
     {"popup_create",	2, 2, f_popup_create},
     {"popup_getoptions", 1, 1, f_popup_getoptions},
     {"popup_getpos",	1, 1, f_popup_getpos},