patch 9.1.0705: Sorting of fuzzy filename completion is not stable

Problem:  Sorting of fuzzy filename completion is not stable
Solution: Compare indexes when scores are equal.  Fix some typos.
          (zeertzjq)

closes: #15593

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/search.c b/src/search.c
index e5936d8..a7fd44e 100644
--- a/src/search.c
+++ b/src/search.c
@@ -5217,7 +5217,7 @@
 {
     pos_T	current_pos = *pos;
     pos_T	circly_end;
-    int		found_new_match = FAIL;
+    int		found_new_match = FALSE;
     int		looped_around = FALSE;
 
     if (whole_line)