Change the naming scheme for class field members

I'm not a fan of Hungarian notation, but C++ kind of needs it with its
implicit `this`. And of all the common options for this, I find
suffixing members with an underscore the least offensive one.

src/common/serialization/vst3/plugin/audio-processor.h

@@ -62,7 +62,7 @@ class YaAudioProcessor : public Steinberg::Vst::IAudioProcessor {
      */
     YaAudioProcessor(ConstructArgs&& args) noexcept;
 
-    inline bool supported() const noexcept { return arguments.supported; }
+    inline bool supported() const noexcept { return arguments_.supported; }
 
     /**
      * Message to pass through a call to
@@ -305,7 +305,7 @@ class YaAudioProcessor : public Steinberg::Vst::IAudioProcessor {
     virtual uint32 PLUGIN_API getTailSamples() override = 0;
 
    protected:
-    ConstructArgs arguments;
+    ConstructArgs arguments_;
 };
 
 #pragma GCC diagnostic pop