docs(parameters): add "testing your code" section

[dreamorosi]

Description of your changes

This PR introduces a new section to the Parameters docs. This section features examples and recommendations on how to test end users' code that uses the utility. It shows how to test the code at different levels ranging from mocking the module from the imports, to using spies, to using a 3rd party library for a more fully featured mock API.

Once merged this PR closes #1321.

How to verify this change

See screenshots below that show most/all the parts of the new section:

Related issues, RFCs

Issue number: #1321

Checklist

• My changes meet the tenets criteria
• I have performed a self-review of my own code
• I have commented my code where necessary, particularly in areas that should be flagged with a TODO, or hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding changes to the examples
• My changes generate no new warnings
• The code coverage hasn't decreased
• I have added tests that prove my change is effective and works
• New and existing unit tests pass locally and in Github Actions
• Any dependent changes have been merged and published
• The PR title follows the conventional commit semantics

Breaking change checklist

Is it a breaking change?: NO

• I have documented the migration process
• I have added, implemented necessary warnings (if it can live side by side)

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