patch 8.2.1300: Vim9: optional argument type not parsed properly

Problem:    Vim9: optional argument type not parsed properly.
Solution:   Skip over the "?". (issue #6507)
diff --git a/src/version.c b/src/version.c
index 93bcc43..68c7cf5 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1300,
+/**/
     1299,
 /**/
     1298,