patch 8.2.0681: pattern for 'hlsearch' highlighting may leak

Problem:    Pattern for 'hlsearch' highlighting may leak. (Dominique Pelle)
Solution:   Call end_search_hl() to make sure the previous pattern is freed.
            (closes #6028)
diff --git a/src/version.c b/src/version.c
index 02f7b6e..982ac1f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    681,
+/**/
     680,
 /**/
     679,