patch 9.0.0456: function called at debug prompt is also debugged

Problem:    Function called at debug prompt is also debugged.
Solution:   Reset the debug level while entering the debug command.
            (closes #11118)
diff --git a/src/version.c b/src/version.c
index 3b143a4..85e5a9d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -704,6 +704,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    456,
+/**/
     455,
 /**/
     454,