patch 9.0.1659: Termdebug: default highlight cleared if changing colorscheme

Problem:    Termdebug: default highlight cleared when changing colorscheme.
Solution:   Use a ColorScheme autocommand. (Christian Brabandt, closes #12566,
            closes #12555)
diff --git a/src/version.c b/src/version.c
index a9c61ad..e174f58 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1659,
+/**/
     1658,
 /**/
     1657,