DOC: Desalination documentation

[fletchapin]

• I have reviewed the documentation on main here.

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Location of Documentation

The entire documentation needs to be updated to include the desalination-related code changes made in #89

Documentation Problem

For example, there is now documentation on the StaticMixer node or Delivery connection. There are a number of other new types and classes that need to be documented.

Suggested Fix

The existing files in the docs folders should be updated to include the new classes and types. These files include node.rst, json_rep.rst, connection.rst, parse_json.rst, and utils.rst