patch 8.2.4724: current instance of last search pattern not easily spotted

Problem:    Current instance of last search pattern not easily spotted.
Solution:   Add CurSearch highlighting. (closes #10133)
diff --git a/src/highlight.c b/src/highlight.c
index 724c4ba..61fea9a 100644
--- a/src/highlight.c
+++ b/src/highlight.c
@@ -157,6 +157,7 @@
     "default link QuickFixLine Search",
     "default link CursorLineSign SignColumn",
     "default link CursorLineFold FoldColumn",
+    "default link CurSearch Search",
     CENT("Normal cterm=NONE", "Normal gui=NONE"),
     NULL
 };