seems linkchecker isn't catching them because it runs on generated html.
at that point the links are already missing.
the generation process seems to strip invalid references when they can't
be re-written from md to html.
I used https://github.com/tcort/markdown-link-check to check the doc
source directly.
There are a few false positives on localhost for development.
PromptLayer now has support for [several different tracking
features.](https://magniv.notion.site/Track-4deee1b1f7a34c1680d085f82567dab9)
In order to use any of these features you need to have a request id
associated with the request.
In this PR we add a boolean argument called `return_pl_id` which will
add `pl_request_id` to the `generation_info` dictionary associated with
a generation.
We also updated the relevant documentation.
