message: feat: add action to status bar
  If not on a pull request branch the default action is now to checkout a
  pull request. Also this adds a tooltip to the icon.
  Closes
diff: @@ -64,8 +64,8 @@ export class StatusBarManager {
  this.statusBar.show();
  this.statusBar.color = colors.none;
  this.statusBar.text = `${githubPullRequestIcon}`;
  - this.statusBar.tooltip = '';
  - this.statusBar.command = '';
  + this.statusBar.tooltip = 'Not on a pull request branch. Click to checkout pull request';
  + this.statusBar.command = 'vscode-github.checkoutPullRequests';
  }
  }
  