Expand xquartz zap stanza
Update gitbook to use GitHub release

The maintainers of this app are no longer supporting the desktop
version, in favor of the web app. The latest desktop release is
no longer available from their website, but can be downloaded as
a GitHub release.
Merge pull request #8541 from jawshooah/gitbook/fix-gitbook

Update gitbook to use GitHub release
Merge pull request #8536 from Dremora/xquartz

Expand xquartz zap stanza