docs(parameters): add testing your code section

[to-mc]

Issue #, if available: #1009

Description of changes:

Add "Testing your code" section to the documentation for parameters utility.

Checklist

• Meet tenets criteria
• Update tests
• Update docs
• PR title follows conventional commit semantics

Breaking change checklist

RFC issue #:

• Migration process documented
• Implement warnings (if it can live side by side)

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

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View rendered docs/utilities/parameters.md

[codecov-commenter]

Codecov Report

Merging #1017 (5e399b6) into develop (6869155) will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #1017   +/-   ##
========================================
  Coverage    99.96%   99.96%           
========================================
  Files          119      119           
  Lines         5347     5364   +17     
  Branches       610      612    +2     
========================================
+ Hits          5345     5362   +17     
  Partials         2        2           

Impacted Files	Coverage Δ
aws_lambda_powertools/utilities/batch/sqs.py	100.00% <0.00%> (ø)

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[heitorlessa]

Looks great! One potential typo on mocking the incorrect namespace, and one question on whether a function factory would be more powerful as an example