docs: truncated configuration section at readthedocs.io

[pjonsson]

The documentation at https://datacube-explorer.readthedocs.io/en/latest/config.html#configuring-from-environment-variables seems to be cut off before the code-block:

         $ export FLASK_ENV=development
         $ export FLASK_APP=cubedash
         $ export CUBEDASH_DEFAULT_TIMEZONE=Australia/Darwin
         $ cubedash-run
          * Running on http://localhost:8080/ (Press CTRL+C to quit)

that sets environment variables, see attached screenshot depicting the bottom of the page.

This is on Ubuntu 22.04. I get the same truncation in Chromium and Firefox.