general: Convert use_docked_mode to an enumeration

Allows some special interactions with it in the Qt frontend.

src/common/settings.h

@@ -379,7 +379,13 @@ struct Values {
 
     Setting<s32> current_user{linkage, 0, "current_user", Category::System};
 
-    SwitchableSetting<bool> use_docked_mode{linkage, true, "use_docked_mode", Category::System};
+    SwitchableSetting<ConsoleMode> use_docked_mode{linkage,
+                                                   ConsoleMode::Docked,
+                                                   "use_docked_mode",
+                                                   Category::System,
+                                                   Specialization::Radio,
+                                                   true,
+                                                   true};
 
     // Controls
     InputSetting<std::array<PlayerInput, 10>> players;

src/common/settings_common.h

@@ -56,6 +56,7 @@ enum Specialization : u8 {
     Scalar = 5,      // Values are continuous
     Countable = 6,   // Can be stepped through
     Paired = 7,      // Another setting is associated with this setting
+    Radio = 8,       // Setting should be presented in a radio group
 
     Percentage = (1 << SpecializationAttributeOffset), // Should be represented as a percentage
 };

src/common/settings_enums.h

@@ -146,6 +146,8 @@ ENUM(AntiAliasing, None, Fxaa, Smaa, MaxEnum);
 
 ENUM(AspectRatio, R16_9, R4_3, R21_9, R16_10, Stretch);
 
+ENUM(ConsoleMode, Handheld, Docked);
+
 template <typename Type>
 inline std::string CanonicalizeEnum(Type id) {
     const auto group = EnumMetadata<Type>::Canonicalizations();