patch 8.0.1713: terminal debugger doesn't handle arguments

Problem:    Terminal debugger doesn't handle arguments.
Solution:   Use <f-args> and pass all the arguments to gdb, e.g. the core file
            or process number. (suggested by Christian Brabandt) Disallow
            starting the debugger twice.
diff --git a/src/version.c b/src/version.c
index 41b9721..b76ccf4 100644
--- a/src/version.c
+++ b/src/version.c
@@ -763,6 +763,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1713,
+/**/
     1712,
 /**/
     1711,