docs: ulwazi doc code blocks

*Please describe the question or issue you're facing with "Test the Ulwazi theme - Documentation starter pack documentation".*

* The code block in the "html_context in conf.py" section has no closing parenthesis for the license part
* When I added one, it still refused to build because of invalid syntax (a "missing comma" apparently)
* In the "Required variables" section, going back to `github_repo = ` may cause problems for docs that are based on Launchpad (which is why the SP originally moved away from the github naming for variables iirc)
* Again in html_context, does the addition of the variables related to the feedback button imply that we need to remove the references to the feedback button from the SP? (presumably there will be conflicts if they are set differently?)
* I'm not sure what "Canonical product menu" produces?
* Might want to revisit the ordering of the doc, I got a bit lost going back and forth between sections (especially towards the end)

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*Reported from: https://canonical-starter-pack.readthedocs-hosted.com/stable/how-to/test-ulwazi-theme/*