Preserve external simulator recommendations. (#3108)
Preserve external simulator recommendations. (#3108)

This copies changes from #2811 into the Jupyter notebook.
quantumlib/Cirq,quantumlib/Cirq,balopat/Cirq,balopat/Cirq,quantumlib/Cirq,balopat/Cirq,quantumlib/Cirq,quantumlib/Cirq