Add initial line segment when adding arc to wxGraphicsPath with GDI+

For the sake of compatibility with Cairo (and Direct2D) an initial line segment should be added to the path from the current point (if set) to the beginning of the arc.

Closes #17557

src/msw/graphicsd2d.cpp

@@ -1416,7 +1416,7 @@ void wxD2DPathData::AddArc(wxDouble x, wxDouble y, wxDouble r, wxDouble startAng
 {
     double angle;
 
-    // For the sake of consistency normalize angles the same way
+    // For the sake of compatibility normalize angles the same way
     // as it is done in Cairo.
     if ( clockwise )
     {
@@ -1450,6 +1450,9 @@ void wxD2DPathData::AddArc(wxDouble x, wxDouble y, wxDouble r, wxDouble startAng
     wxPoint2DDouble start = wxPoint2DDouble(cos(startAngle) * r, sin(startAngle) * r);
     wxPoint2DDouble end = wxPoint2DDouble(cos(endAngle) * r, sin(endAngle) * r);
 
+    // To ensure compatibility with Cairo an initial
+    // line segment to the beginning of the arc needs
+    // to be added to the path.
     if (m_figureOpened)
     {
         AddLineToPoint(start.m_x + x, start.m_y + y);