patch 9.1.1475: completion: regression when "nearest" in 'completeopt'

Problem:  completion: regression when "nearest" in 'completeopt'
Solution: fix compare function (Girish Palya)

closes: #17577

Signed-off-by: Girish Palya <girishji@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/insexpand.c b/src/insexpand.c
index 94eb760..ed1b5ff 100644
--- a/src/insexpand.c
+++ b/src/insexpand.c
@@ -1404,7 +1404,7 @@
 {
     int score_a = ((compl_T*)a)->cp_score;
     int score_b = ((compl_T*)b)->cp_score;
-    if (score_a < 0 || score_b < 0)
+    if (score_a == 0 || score_b == 0)
 	return 0;
     return (score_a > score_b) ? 1 : (score_a < score_b) ? -1 : 0;
 }