patch 8.2.1604: Vim9: cannot use "true" with getcompletion()

Problem:    Vim9: cannot use "true" with getcompletion().
Solution:   use tv_get_bool_chk(). (closes #6875)
diff --git a/src/version.c b/src/version.c
index 7ce5eb2..6b71a14 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1604,
+/**/
     1603,
 /**/
     1602,