This is a report for github staff / team members. If there is a more appropriate place to submit documentation feedback, please let me know.
My interpretation is that this should be `github.event_name` NOT `gihub.event_name`.
@csumpter That is definitely a typo! I just fixed that and the latest update is live on the site.Thanks for letting us know about this and always feel free to contact the Support team at https://support.github.com/contact if you have suggestions or find issues in the docs.