Add COLIBRI smtlib description

1 job for colibri in 2 minutes and 36 seconds (queued for 3 seconds)
Name Stage Failure
failed
pages Deploy
HTTP request sent, awaiting response... 302 Found
Location: https://git.frama-c.com/pub/colibrics/-/jobs/550350/artifacts/raw/farith2_doc.tar.gz [following]
--2022-07-04 08:30:12-- https://git.frama-c.com/pub/colibrics/-/jobs/550350/artifacts/raw/farith2_doc.tar.gz
Reusing existing connection to git.frama-c.com:443.
HTTP request sent, awaiting response... 404 Not Found
2022-07-04 08:30:12 ERROR 404: Not Found.

Cleaning up project directory and file based variables
ERROR: Job failed: exit code 1