Missing code block in `declare-an-experiment-to-observe-the-weakness`

[ciaransweet]

The section here https://chaostoolkit.org/reference/tutorial/#declare-an-experiment-to-observe-the-weakness is missing the json that is meant to be populating it:

https://github.com/chaostoolkit/chaostoolkit-documentation/blob/e18cb5c3886de614e5f9a3f3cf44abc0ab266a2c/sources/reference/tutorial.md#L111-L114

[ciaransweet]

We're missing out the git submodule update --init call that should be here https://github.com/chaostoolkit/chaostoolkit-documentation/blob/e18cb5c3886de614e5f9a3f3cf44abc0ab266a2c/.github/workflows/build.yaml#L60-L61