patch 8.2.0512: Vim9: no optional arguments in func type

Problem:    Vim9: no optional arguments in func type.
Solution:   Check for question mark after type.  Find function reference
            without function().
diff --git a/src/testdir/Make_all.mak b/src/testdir/Make_all.mak
index d0bfe1c..1a47cfc 100644
--- a/src/testdir/Make_all.mak
+++ b/src/testdir/Make_all.mak
@@ -274,6 +274,7 @@
 	test_vartabs \
 	test_vim9_disassemble \
 	test_vim9_expr \
+	test_vim9_func \
 	test_vim9_script \
 	test_viminfo \
 	test_vimscript \
@@ -483,6 +484,7 @@
 	test_vartabs.res \
 	test_vim9_disassemble.res \
 	test_vim9_expr.res \
+	test_vim9_func.res \
 	test_vim9_script.res \
 	test_viminfo.res \
 	test_vimscript.res \