use new standard "anywhere" hotkey in Gui

plugins/command-prompt.cpp

@@ -337,17 +337,14 @@ command_result show_prompt(color_ostream &out, std::vector <std::string> & param
     Screen::show(dts::make_unique<viewscreen_commandpromptst>(params), plugin_self);
     return CR_OK;
 }
-bool hotkey_allow_all(df::viewscreen *top)
-{
-    return true;
-}
+
 DFhackCExport command_result plugin_init(color_ostream &out, std::vector <PluginCommand> &commands)
 {
     commands.push_back(PluginCommand(
                 "command-prompt",
                 "Allows you to run a DFHack command from in-game.",
                 show_prompt,
-                hotkey_allow_all));
+                Gui::anywhere_hotkey));
     return CR_OK;
 }