We should recommend hypothesis for testing

[paddyroddy]

Is Your Feature Request Related to a Problem? Please Describe

Have used it myself in the past https://github.com/astro-informatics/sleplet/blob/8910cd56c3bb39edb265184f78a7c743b1ffff20/tests/test_translation.py#L22-L41, but have just learnt about the ghostwriting feature which writes tests for you! Super cool.

Describe the Solution You'd Like

We should document hypothesis with a traffic light symbol

Describe Alternatives You've Considered

No response

Additional Context

No response

[dstansby]

👍 I've used it before, found it to be very helpful and with great docs so I think should go in as a 🟢

[samcunliffe]

Fixed via #467