Have a context menu to clear review status

[bpasero]

Here in "File" node there could be a context menu to either check or uncheck all checkboxes:

[alexr00]

If you use a tree structure for files then you get this by checking/unchecking a folder checkbox.

A few ideas for the flat structure:

• Support multi select, then you select all so toggling 1 checkbox would toggle all.
• Add a checkbox on "Files"
• Add an inline action on "File" for "mark all as viewed"/"mark all as unviewed"

[bpasero]

I like the idea of multi-select!

[alexr00]

Once https://github.com/microsoft/vscode-pull-request-github/pull/6570 is in you can do the following for checked out PRs in the active PR view:

• multi-select files
• check/uncheck them
• If your check/uncheck is part of the selection, then the entire selection will be toggled.

[benibenj]

This works as mentioned above, however, it feels a bit weird to me that all checkboxes are toggled. I would have expected that all selected checkboxes have the same state after toggling one.

So if I have [ ] [x] [ ] and select all and toggle the first checkbox I would expect to end up with [x] [x] [x]. Instead I get [x] [ ] [x].

Also, this only works for the GitHub Pull Request view and not for the GitHub Pull Requests view