Changes

• Enable pixel-wise mouse reporting over Win32 Console API.
  Pixel-wise or fractional coordinates are 32-bit floating-point numbers that represent the position of the mouse cursor relative to the console's grid of text cells. Screen pixel coordinates can be calculated by multiplying the fractional coordinates by the cell size.
  Fractional mouse coordinates are critical to UX. In particular, this directly relates to the sensitivity of scrollbars, where moving the mouse pointer even one pixel can cause content to scroll several lines.
  On Windows, when using the Win32 Console API, vtm now reports mouse events with fractional mouse coordinates.

  For example, run the following snippet inside vtm and then in classic Windows Command Prompt outside vtm:

  #include <iostream>
  #include <vector>
  #include <windows.h>
  
  static constexpr auto custom_type = 0b1000'0000'0000'0000;
  static constexpr auto fp2d_mouse = 3;
  struct fp2d_mouse_input : MENU_EVENT_RECORD // MENU_EVENT_RECORD structure extension.
  {
      //DWORD EventType   = MENU_EVENT;
      //DWORD dwCommandId = custom_type | fp2d_mouse;
      float x; // Floating point mouse x coord.
      float y; // Floating point mouse y coord.
  };
  int main()
  {
      auto inp = ::GetStdHandle(STD_INPUT_HANDLE);
      ::SetConsoleMode(inp, ENABLE_EXTENDED_FLAGS | ENABLE_MOUSE_INPUT);
      auto r = INPUT_RECORD{};
      auto count = DWORD{};
      auto x = std::numeric_limits<float>::quiet_NaN();
      auto y = std::numeric_limits<float>::quiet_NaN();
      auto mouse_out = false;
      std::cout << "Press any mouse button to exit\n";
      while (true)
      {
          ::ReadConsoleInputW(inp, &r, 1, &count);
          if (r.EventType == MENU_EVENT)
          {
              if (r.Event.MenuEvent.dwCommandId == (custom_type | fp2d_mouse)) // The floating point coordinates message always precedes the classic mouse report.
              {
                  x = reinterpret_cast<fp2d_mouse_input*>(&r.Event.MenuEvent)->x;
                  y = reinterpret_cast<fp2d_mouse_input*>(&r.Event.MenuEvent)->y;
                  mouse_out = std::isnan(x); // NaN is a sign that the mouse has gone away or is disconnected.
                  if (mouse_out) std::cout << "The mouse has left the window\n";
              }
          }
          else if (r.EventType == MOUSE_EVENT && !mouse_out)
          {
              if (r.Event.MouseEvent.dwButtonState) return 0;
              if (std::isnan(x)) // Classical behavior.
              {
                  std::cout << "MOUSE_EVENT coord: " << r.Event.MouseEvent.dwMousePosition.X << "," << r.Event.MouseEvent.dwMousePosition.Y << "\n";
              }
              else // Floating point mouse coordinates.
              {
                  std::cout << "MOUSE_EVENT coord: " << x << "," << y << "\n";
              }
          }
      }
  }