dispatcher: uses type_id_v rather than a family

test/plugin/dispatcher/plugin.cpp

@@ -0,0 +1,18 @@
+#include <cr.h>
+#include <entt/signal/dispatcher.hpp>
+#include "types.h"
+
+CR_EXPORT int cr_main(cr_plugin *ctx, cr_op operation) {
+    switch (operation) {
+    case CR_STEP:
+        static_cast<entt::dispatcher *>(ctx->userdata)->trigger<message>(42);
+        break;
+    case CR_LOAD:
+    case CR_UNLOAD:
+    case CR_CLOSE:
+        // nothing to do here, this is only a test.
+        break;
+    }
+
+    return 0;
+}