patch 8.2.0606: several syntax HL errors not checked

Problem:    Several syntax HL errors not checked.
Solution:   Add tests. (Yegappan Lakshmanan, closes #5954)
diff --git a/src/version.c b/src/version.c
index 7af2e50..b95c7ee 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    606,
+/**/
     605,
 /**/
     604,