Apply requested changes from code review
Apply requested changes from code review

Coverage now only runs under Linux stable in order to upload the results only once. Tarpaulin now also uses documentation tests for the measurements. The Codecov upload does not use an environment variable anymore.

Co-authored-by: Sunjay Varma <7704b6fec7f8103a19c0517db5ea033da8571b31@users.noreply.github.com>
sunjay/turtle,sunjay/turtle,sunjay/turtle