Add ShareData files member

[ewilligers]

https://wicg.github.io/web-share/#sharedata-dictionary has

dictionary ShareData {
  sequence<File> files;
  ...
};

lib/lib.dom.d.ts and src/lib/dom.generated.d.ts describe ShareData, but not the files member, which is now supported by Blink, Firefox and Safari.

I suspect the following needs to be added:
files?: File[];

CC @orta

[orta]

Like the spec file needs an update over on https://github.com/microsoft/TypeScript-DOM-lib-generator/ - I'm moving this issue to that repo.

[saschanaz]

#1034 added it

@github-actions close

[github-actions]

Closing because @saschanaz is one of the code-owners of this repository.