Improve LinkDetector

[dgozman]

@isidorn Could you please take a look? This implements some improvements. We can try to unify with terminal link handling, however it doesn't seem to be straightforward because the control flow is very different.

• recognizes web urls;
• checks that file path exists;
• supports relative to workspace root paths (./foo);
• supports relative to home dir paths (~/foo);
• optional line/column;
• smoke test.

[isidorn]

I really really like this work. I just left one minor comment in the code.
It's great that you added tests!

I did not code review the linkDetector.ts. I trust that you did it properly and If the tests are good and if it is behaving fine it is perfetly fine for me - that is why I would like it to be pushed to insiders so we start self hosting on it. Also I hope that it is ok for you if I from now on treat you as the owner of the linkDetector, thus I might ping you on potential incoming issues?
Also if there is some part of the linkDetector that you would like me to review let me know and I can give it a deeper review. Thanks!

[dgozman]

Thank you, this sounds good to me. I did address the comments.

There was a small change in behavior - we don't wrap text with extra span when not required. From manual testing, I didn't find any issues with that.

[isidorn]

Great, thanks for addressing the comments. Merging this in so we start self hosting on it already.
Thanks again for this contribution!