Keyboard Enhancements for Azure DevOps door Tau

Provides some enhancement to the keyboard navigation
in Azure DevOps:

• Press x to mark a file as reviewed
• Using ↑ (arrow up) and ↓ (arrow down) in a PR file list will activate that file.
  Hold ⇧ (shift) to revert to the default behaviour (focus only).

Self-hosted instances of Azure DevOps are supported;
add your custom domain in the extension settings.