Add typescript to demo package.json and add more descriptive filters for demo/src/dialog.tab.ts

[Cyan903]

I found this repository while searching for an electron dialog bridge. This works great for what I'm using it for, but I had some small issues setting up the demo. npm build would not run because typescript wasn't installed. After I installed that, the demo worked perfectly.

I also thought it would be a good idea to make the filter name more descriptive. When trying to open a file, some file managers (like Thunar) do not show the extension and only show the name which is somewhat confusing.

Other than that, this bridge works great. Thanks for making this. I was looking forever for something like this.

[poirierlouis]

Hello,
Thank you for your feedback.
In deed, the demo is not complete and missing stuff.

I'll take a look into your PR.