patch 9.1.0604: popup_filter during Press Enter prompt seems to hang

Problem:  popup_filter during Press Enter prompt seems to hang
Solution: Return early, when need_wait_return is set
          (Ernie Rael)

fixes: #15300
closes: #15301

Signed-off-by: Ernie Rael <errael@raelity.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/popupwin.c b/src/popupwin.c
index 9d60aa2..0ff57fb 100644
--- a/src/popupwin.c
+++ b/src/popupwin.c
@@ -2651,6 +2651,8 @@
 	return;
 
     c = *key;
+    if (c == CAR && need_wait_return)
+	return;
     if (c == K_SPECIAL && key[1] != NUL)
 	c = TO_SPECIAL(key[1], key[2]);