Adds a font contained in system memory to this System.Drawing.Text.PrivateFontCollection.
To use the memory font, text on a control must be rendered with GDI+. Use the System.Windows.Forms.Application.SetCompatibleTextRenderingDefault(bool) method, passing true, to set GDI+ rendering on the application, or on individual controls by setting the control's System.Windows.Forms.GroupBox.UseCompatibleTextRendering property to true. Some controls cannot be rendered with GDI+.