Fix warning in Visual Studio.

Fix formatting to match other classes.

src/emucore/Cart2K.cxx

@@ -46,7 +46,7 @@ Cartridge2K::Cartridge2K(const ByteBuffer& image, size_t size,
   else
   {
     // Manually 'mirror' the ROM image into the buffer
-    for(int i = 0; i < System::PAGE_SIZE; i += mySize)
+    for(size_t i = 0; i < System::PAGE_SIZE; i += mySize)
       std::copy_n(image.get(), mySize, myImage.get() + i);
     mySize = System::PAGE_SIZE;
   }

src/emucore/Lightgun.hxx

@@ -26,7 +26,7 @@
 
 class Lightgun : public Controller
 {
-public:
+  public:
     /**
       Create a new lightgun controller plugged into the specified jack
 
@@ -41,7 +41,7 @@ public:
              const string& romMd5, const FrameBuffer& frameBuffer);
     virtual ~Lightgun() = default;
 
-public:
+  public:
     using Controller::read;
 
     /**
@@ -63,13 +63,13 @@ public:
     */
     string name() const override { return "Lightgun"; }
 
-private:
+  private:
     const FrameBuffer& myFrameBuffer;
 
     // targetting compensation values
     Int32 myOfsX{0}, myOfsY{0};
 
-private:
+  private:
     // Following constructors and assignment operators not supported
     Lightgun() = delete;
     Lightgun(const Lightgun&) = delete;