configuration_shared: Add some comments

Monke brain can't remember what all of these does a year later.

src/yuzu/configuration/configuration_shared.h

@@ -15,23 +15,24 @@ constexpr int USE_GLOBAL_INDEX = 0;
 constexpr int USE_GLOBAL_SEPARATOR_INDEX = 1;
 constexpr int USE_GLOBAL_OFFSET = 2;
 
+// CheckBoxes require a tracker for their state since we emulate a tristate CheckBox
 enum class CheckState {
-    Off,
-    On,
-    Global,
-    Count,
+    Off,    // Checkbox overrides to off/false
+    On,     // Checkbox overrides to on/true
+    Global, // Checkbox defers to the global state
+    Count,  // Simply the number of states, not a valid checkbox state
 };
 
 // Global-aware apply and set functions
 
+// ApplyPerGameSetting, given a Settings::Setting and a Qt UI element, properly applies a Setting
 void ApplyPerGameSetting(Settings::Setting<bool>* setting, const QCheckBox* checkbox,
                          const CheckState& tracker);
 void ApplyPerGameSetting(Settings::Setting<int>* setting, const QComboBox* combobox);
 void ApplyPerGameSetting(Settings::Setting<Settings::RendererBackend>* setting,
                          const QComboBox* combobox);
-void ApplyPerGameSetting(Settings::Setting<Settings::GPUAccuracy>* setting,
-                         const QComboBox* combobox);
 
+// Sets a Qt UI element given a Settings::Setting
 void SetPerGameSetting(QCheckBox* checkbox, const Settings::Setting<bool>* setting);
 void SetPerGameSetting(QComboBox* combobox, const Settings::Setting<int>* setting);
 void SetPerGameSetting(QComboBox* combobox,
@@ -39,13 +40,20 @@ void SetPerGameSetting(QComboBox* combobox,
 void SetPerGameSetting(QComboBox* combobox,
                        const Settings::Setting<Settings::GPUAccuracy>* setting);
 
+// (Un)highlights a Qt UI element
 void SetHighlight(QWidget* widget, bool highlighted);
+
+// Sets up a QCheckBox like a tristate one, given a Setting
 void SetColoredTristate(QCheckBox* checkbox, const Settings::Setting<bool>& setting,
                         CheckState& tracker);
 void SetColoredTristate(QCheckBox* checkbox, bool global, bool state, bool global_state,
                         CheckState& tracker);
+
+// Sets up coloring of a QWidget `target` based on the state of a QComboBox, and calls
+// InsertGlobalItem
 void SetColoredComboBox(QComboBox* combobox, QWidget* target, int global);
 
+// Adds the "Use Global Configuration" selection and separator to the beginning of a QComboBox
 void InsertGlobalItem(QComboBox* combobox, int global_index);
 
 } // namespace ConfigurationShared