patch 8.2.0570: Vim9: no error when omitting type from argument

Problem:    Vim9: no error when omitting type from argument.
Solution:   Enforce specifying argument types.
diff --git a/src/ex_eval.c b/src/ex_eval.c
index 72da2f2..7ffc145 100644
--- a/src/ex_eval.c
+++ b/src/ex_eval.c
@@ -2273,9 +2273,12 @@
  * ":endfunction" when not after a ":function"
  */
     void
-ex_endfunction(exarg_T *eap UNUSED)
+ex_endfunction(exarg_T *eap)
 {
-    emsg(_("E193: :endfunction not inside a function"));
+    if (eap->cmdidx == CMD_enddef)
+	emsg(_("E193: :enddef not inside a function"));
+    else
+	emsg(_("E193: :endfunction not inside a function"));
 }
 
 /*