Updates API and contributor documentation for writing integrations
for the new `generate-integration-url.md` macro. Removes all
refrences to `create-bot-construct-url.md`, which was removed in
the previous commit.
The python code snippet referred to exactly doesn't exists.
This commit changes it to the exact code present in
"zerver/lib/integrations.py", which has a type annotation.
- Updates `.prettierignore` for the new directory.
- Updates any reference to the API documentation directory for
markdown files to be `api_docs/` instead of `zerver/api/`.
- Removes a reference link from `docs/documentation/api.md` that
hasn't referenced anything in the text since commit 0542c60.
- Update rendering of API documentation for new directory.
Lauryn Menard
David Rosa
Satyam Bansal
Anders Kaseorg