Add enum DebugConsoleMode

[smart-bo]

What it does

Fixes: #10009

Add enum DebugConsoleMode to theia.d.ts

How to test

• confirm that references to DebugConsoleMode now can correctly go to definition in theia.d.ts

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[vince-fugnitto]

The changes look good to me 👍

[vince-fugnitto]

@smart-bo in case you were not aware, you can link issues with keywords so that they are automatically closed when the pull-request is merged. I've taken the liberty of updating the pull-request description to do so 👍