patch 8.2.1707: small inconsitency in highlight test

Problem:    Small inconsitency in highlight test.
Solution:   Use one argument for :execute. (Antony Scriven, #6975)
diff --git a/src/version.c b/src/version.c
index 93f7701..fd880f5 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1707,
+/**/
     1706,
 /**/
     1705,