patch 8.1.0018: using "gn" may select wrong text when wrapping

Problem:    Using "gn" may select wrong text when wrapping.
Solution:   Avoid wrapping when searching forward. (Christian Brabandt)
diff --git a/src/version.c b/src/version.c
index 4e4c1fb..1f8cfef 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    18,
+/**/
     17,
 /**/
     16,