fix customizing the response builder example

[jcmcclorey]

This pull request...

• [x] Closes #TICKET-NUMBER

Checklist:

• [x] I have opened the issue ticket that this pull request is part of.
• [x] This pull request title contains (#TICKET-NUMBER) for reference.
• [x] This pull request description contains Closes #{$ISSUE_NO} that closes ticket.
• [x] This pull request is all my own work - I have not plagiarized.
• [x] This contribution is licensed under MIT or compatible license.
• [x] All code is covered in unit tests and all tests pass.
• [x] I have updated the docs to cover my changes (if applicable).
• [x] All function parameters and return values are annotated with PHP type hints.
• [x] All functions have PHPDocs blocks.