patch 8.2.0295: highlighting for :s wrong when using different separator

Problem:    Highlighting for :s wrong when using different separator.
Solution:   Use separat argument for search direction and separator. (Rob
            Pilling, closes #5665)
diff --git a/src/normal.c b/src/normal.c
index 512b799..df2cf53 100644
--- a/src/normal.c
+++ b/src/normal.c
@@ -4304,7 +4304,7 @@
     curwin->w_set_curswant = TRUE;
 
     vim_memset(&sia, 0, sizeof(sia));
-    i = do_search(cap->oap, dir, pat, cap->count1,
+    i = do_search(cap->oap, dir, dir, pat, cap->count1,
 			    opt | SEARCH_OPT | SEARCH_ECHO | SEARCH_MSG, &sia);
     if (wrapped != NULL)
 	*wrapped = sia.sa_wrapped;