Fix acquiring HDC from wxGCDC with non-GDI+ graphics context

HDC can be acquired/released only when wxGCDC is associated with GDI+
graphics context.

Closes #19207.

interface/wx/renderer.h

@@ -306,6 +306,9 @@ public:
     it changes them, so it is safe to assume that the same pen, brush and colours
     that were active before the call to this function are still in effect after it.
 
+    @note Under wxMSW drawing on wxGCDC is possible only if it's associated with
+    GDI+ wxGraphicsContext.
+
     @library{wxcore}
     @category{gdi}
 */