docs: Add page on integrating a new action

Author: cassava

docs/contributing.rst

@@ -43,7 +43,6 @@ certainly require some changes before accepting.
    :maxdepth: 2
 
    contributing/creating-a-new-release
-   contributing/adding-a-new-action
    contributing/recording-with-asciinema
 
    contributing/git-guidelines

docs/develop.rst

@@ -21,5 +21,6 @@ For standard installation instructions please refer to the :doc:`installation gu
    develop/new-controller
    develop/integrating-a-controller
    develop/debugging-a-controller
+   develop/adding-a-new-action
 
    develop/cloe-ui

docs/contributing/adding-a-new-action.rst renamed to docs/develop/adding-a-new-action.rst

@@ -39,8 +39,9 @@ Then we come to the source for the ``Log`` action:
      Log(const std::string& name, LogLevel level, const std::string& msg)
          : Action(name), level_(level), msg_(msg) {}
      ActionPtr clone() const override { return std::make_unique<Log>(name(), level_, msg_); }
-     void operator()(const Sync&, TriggerRegistrar&) override {
+     CallbackResult operator()(const Sync&, TriggerRegistrar&) override {
        logger()->log(level_, msg_.c_str());
+       return CallbackResult::Ok;
      }
      bool is_significant() const override { return false; }