SCM View Should Allow Multi-Select

[tsmaeder]

One can only select single entries in the "Source Control" view. This is annoying when trying to stage multiple changes in git, for example.

To reproduce:

1. Make changes in multiple files in a git project in your workspace
2. Go to the "Source Control" view
3. Observe: you see the changed files under "Changes"
4. Shift-Click or Ctrl-Click multiple files in the view
5. Observe: as soon as you click a second file, the selection on the first goes away

Multi-select works in this view in VS Code (and it's mighty useful, I dare say)

[vince-fugnitto]

@tsmaeder is it fine to close the original, the issue is a duplicate of #1318

[tsmaeder]

🤷 I was looking for "scm" issues. I would suspect this is not git specific?

[vince-fugnitto]

🤷 I was looking for "scm" issues. I would suspect this is not git specific?

I believe it is the same problem, the original was named git since we had no notion of scm before. I'll close the original in favor of this one as it is newer and more up to date :)

[westbury]

This should be easy once #7505 is merged. That PR re-writes the source control view to use tree-widget, so we can use the same selection code. Also that PR adds support for an array of ScmResource in the context menu args (previously just a single ScmResource allowed), and downstream dugite API adjusted to accept multiples. This was actually done to support actions on folders. As I already know the changes required here, I'll prepare the PR and submit it once #7505 is merged.