Let terminal consumers provide click handlers and pattern recognizers for buffer text

[ZoeyR]

Description of the new feature/enhancement

Terminal consumers have a need to provide their own handlers for clickable regions of text in the terminal. For example: In VS this could enable clicking on build errors and opening up a document to the line and column called out in the error.

Proposed technical implementation details (optional)

There needs to be two additions to the terminal in order to enable this:

• Consumers of the terminal must be able to provide a pattern that will identify regions of clickable text
• Consumers will provide a callback that is called with the clicked text as a parameter

[DHowett]

This will require some part of #204/#574, but is a distinct ask that control consumers be able to add matching conditions and intercept click events.

[DHowett]

Triaged into BL, Spec needed.

[vnagarnaik]

Would it be possible to work on this FR, now that the #204/#574 have been closed?

[zadjii-msft]

I don't see why not, but whatever design we come up with should appropriately account for #8849, #7562, #8294, #2671, et. al. in #5001.

Actually, should this just be duped to some combination of those?

[zadjii-msft]

I'm leaving this open and separate from #8849 because of one key factor:

For example: In VS this could enable clicking on build errors and opening up a document to the line and column called out in the error.

The ControlInteractivity needs a way of raising these events up to the hosting application to figure out what to do with them, not just the TermControl. Right now the control only really recognizes "ShellExecute this URL" as an action. People using the WPFControl will need to be able to say "If you see this pattern, then raise some identifier type of event", and be able to handle that event.