InputCommon: Use nested namespace specifiers where applicable

Source/Core/InputCommon/ControllerInterface/XInput/XInput.cpp

@@ -8,9 +8,7 @@
 #define XINPUT_GAMEPAD_GUIDE 0x0400
 #endif
 
-namespace ciface
-{
-namespace XInput
+namespace ciface::XInput
 {
 static const struct
 {
@@ -243,5 +241,4 @@ void Device::Motor::SetState(ControlState state)
   m_motor = (WORD)(state * m_range);
   m_parent->UpdateMotors();
 }
-}  // namespace XInput
-}  // namespace ciface
+}  // namespace ciface::XInput

Source/Core/InputCommon/ControllerInterface/XInput/XInput.h

@@ -18,9 +18,7 @@
 #error You are building this module against the wrong version of DirectX. You probably need to remove DXSDK_DIR from your include path and/or _WIN32_WINNT is wrong.
 #endif
 
-namespace ciface
-{
-namespace XInput
+namespace ciface::XInput
 {
 void Init();
 void PopulateDevices();
@@ -105,5 +103,4 @@ private:
   const BYTE m_subtype;
   const u8 m_index;
 };
-}  // namespace XInput
-}  // namespace ciface
+}  // namespace ciface::XInput