Make Module.open?/1 and family to match their docs (#9278)

* Make Module.open?/1 and family to match their docs.

* Cosmetics.

* Introduced internal not_closing state for modules.

It’s stored in a separate ETS and the last field of #elixir_code_server state to minimize impact.

* Use the same ETS for the state.

lib/elixir/src/elixir_code_server.erl

@@ -40,6 +40,9 @@ handle_call({defmodule, Module, Pid, Tuple}, _From, Config) ->
 handle_call({undefmodule, Ref}, _From, Config) ->
   {reply, ok, undefmodule(Ref, Config)};
 
+handle_call({unopenmodule, Ref}, _From, Config) ->
+  {reply, ok, unopenmodule(Ref, Config)};
+
 handle_call({acquire, Path}, From, Config) ->
   Current = Config#elixir_code_server.required,
   case maps:find(Path, Current) of
@@ -155,3 +158,12 @@ undefmodule(Ref, #elixir_code_server{mod_ets=ModEts} = Config) ->
     error ->
       Config
   end.
+
+unopenmodule(Ref, #elixir_code_server{mod_ets=ModEts} = Config) ->
+  case maps:find(Ref, ModEts) of
+    {ok, Mod} ->
+      ets:update_element(elixir_modules, Mod, {5, false}),
+      Config;
+    error ->
+      Config
+  end.