Discard old pieces between Qed and the next blank line, so that generated...

Discard old pieces between Qed and the next blank line, so that generated commands about implicit arguments are not preserved.

src/printer/coq.ml

@@ -462,7 +462,8 @@ let read_old_script =
       if Str.string_match axm s 0 then
         (let name = Str.matched_group 2 s in sc := Axiom name :: !sc;
         skip_to_empty := true) else
-      if s = "(* Why3 goal *)" then sc := read_old_proof ch :: !sc else
+      if s = "(* Why3 goal *)" then
+        (sc := read_old_proof ch :: !sc; skip_to_empty := true) else
       if s = "(* YOU MAY EDIT THE CONTEXT BELOW *)" then
         (sc := read_deprecated_script ch true; raise End_of_file) else
       if s = "(* YOU MAY EDIT THE PROOF BELOW *)" then