emitter: uses type_id_v rather than a family

test/plugin/emitter/main.cpp

@@ -0,0 +1,26 @@
+#define CR_HOST
+
+#include <cr.h>
+#include <gtest/gtest.h>
+#include <entt/signal/emitter.hpp>
+#include "types.h"
+
+TEST(Lib, Emitter) {
+    test_emitter emitter;
+    int value{};
+
+    emitter.once<event>([&](event ev, test_emitter &) { value = ev.payload; });
+    emitter.once<message>([&](message msg, test_emitter &) { value = msg.payload; });
+    emitter.publish<event>(3);
+
+    ASSERT_EQ(value, 3);
+
+    cr_plugin ctx;
+    ctx.userdata = &emitter;
+    cr_plugin_load(ctx, PLUGIN);
+    cr_plugin_update(ctx);
+
+    ASSERT_EQ(value, 42);
+
+    cr_plugin_close(ctx);
+}