[ScriptUI] reference enums with typeof to access enum properties

[fartinmartin]

The following lines work in ExtendScript, but will cause TypeScript to complain with (ts 2339):

ScriptUI.Alignment.LEFT // Property 'LEFT' does not exist on type '_Alignment'. 
ScriptUI.FontStyle.BOLD // Property 'BOLD' does not exist on type '_FontStyle'.
ScriptUIGraphics.PenType.SOLID_COLOR // Property 'SOLID_COLOR' does not exist on type '_BrushOrPenType'.

This is because in order to access the enum properties we need to reference their types via typeof. This PR adds this:

declare class ScriptUI {
  static readonly Alignment: typeof _Alignment
  static readonly FontStyle: typeof _FontStyle
}

declare class ScriptUIGraphics {
  static readonly BrushType: typeof _BrushOrPenType
  static readonly PenType: typeof _BrushOrPenType
}