Unify handling for *::{get,set}State

Since these functions are exactly the same, and for whatever reason they
didn't just add them to the `IPluginBase` both `IComponent` and
`IEditController`. inherit from

src/plugin/bridges/vst3-impls/plugin-proxy.cpp

@@ -171,22 +171,23 @@ tresult PLUGIN_API Vst3PluginProxyImpl::setActive(TBool state) {
 }
 
 tresult PLUGIN_API Vst3PluginProxyImpl::setState(Steinberg::IBStream* state) {
-    return bridge.send_message(YaComponent::SetState{
+    // Since both interfaces contain this function, this is used for both
+    // `IComponent::setState()` as well as `IEditController::setState()`
+    return bridge.send_message(Vst3PluginProxy::SetState{
         .instance_id = arguments.instance_id, .state = state});
 }
 
 tresult PLUGIN_API Vst3PluginProxyImpl::getState(Steinberg::IBStream* state) {
+    // Since both interfaces contain this function, this is used for both
+    // `IComponent::getState()` as well as `IEditController::getState()`
     const GetStateResponse response = bridge.send_message(
-        YaComponent::GetState{.instance_id = arguments.instance_id});
+        Vst3PluginProxy::GetState{.instance_id = arguments.instance_id});
 
     assert(response.updated_state.write_back(state) == Steinberg::kResultOk);
 
     return response.result;
 }
 
-// FIXME: Fix `{set,get}State()` for `IEditController` as mentioned in the
-//        header
-
 tresult PLUGIN_API
 Vst3PluginProxyImpl::setComponentState(Steinberg::IBStream* state) {
     // TODO: Implement

src/plugin/bridges/vst3-impls/plugin-proxy.h

@@ -81,12 +81,9 @@ class Vst3PluginProxyImpl : public Vst3PluginProxy {
 
     // From `IEditController`
     tresult PLUGIN_API setComponentState(Steinberg::IBStream* state) override;
-    // FIXME: These are duplicate, we need to change the implementation to call
-    //        this on either `object_instances[instance_id].component` or
-    //        `object_instances[instance_id].edit_controller` depending on which
-    //        one exists.
-    // tresult PLUGIN_API setState(Steinberg::IBStream* state) override;
-    // tresult PLUGIN_API getState(Steinberg::IBStream* state) override;
+    // `IEditController` also contains `getState()` and `setState()`  functions.
+    // These are identical to those defiend in `IComponent` and they're thus
+    // handled in in the same function.
     int32 PLUGIN_API getParameterCount() override;
     tresult PLUGIN_API
     getParameterInfo(int32 paramIndex,