The reason for the docs build failure is the fact that the line in build_and_test.yml is failing to install pytket-qiskit.

for w in `find wheelhouse/ -type f -name "*.whl"` ; do poetry run pip install $w ; done

This wasn't showing up as no exit flags were added to the build-docs.sh script. Hence the silent build failure

Note that this doesn't impact the website build but would be nice to have C.I. checks running properly.

See #443

@cqc-melf Also likely to be an issue with other extensions because the docs build c.i. checks are very similar. Worth checking.