configure_audio: Add disambiguation comment for the volume percentage string

Disambiguates what the string represents to help translators more easily
understand what it is that they're translating. While we're at it, we
can move the code to its own function, so that we don't need to specify
the same string twice.

src/yuzu/configuration/configure_audio.cpp

@@ -21,9 +21,8 @@ ConfigureAudio::ConfigureAudio(QWidget* parent)
         ui->output_sink_combo_box->addItem(sink_detail.id);
     }
 
-    connect(ui->volume_slider, &QSlider::valueChanged, [this] {
-        ui->volume_indicator->setText(tr("%1 %").arg(ui->volume_slider->sliderPosition()));
-    });
+    connect(ui->volume_slider, &QSlider::valueChanged, this,
+            &ConfigureAudio::setVolumeIndicatorText);
 
     this->setConfiguration();
     connect(ui->output_sink_combo_box,
@@ -62,7 +61,11 @@ void ConfigureAudio::setConfiguration() {
     ui->audio_device_combo_box->setCurrentIndex(new_device_index);
 
     ui->volume_slider->setValue(Settings::values.volume * ui->volume_slider->maximum());
-    ui->volume_indicator->setText(tr("%1 %").arg(ui->volume_slider->sliderPosition()));
+    setVolumeIndicatorText(ui->volume_slider->sliderPosition());
+}
+
+void ConfigureAudio::setVolumeIndicatorText(int percentage) {
+    ui->volume_indicator->setText(tr("%1%", "Volume percentage (e.g. 50%)").arg(percentage));
 }
 
 void ConfigureAudio::applyConfiguration() {

src/yuzu/configuration/configure_audio.h

@@ -26,6 +26,7 @@ public slots:
 
 private:
     void setConfiguration();
+    void setVolumeIndicatorText(int percentage);
 
     std::unique_ptr<Ui::ConfigureAudio> ui;
 };