Update self-hosting.md documentation for running with Prometheus (#6052)
Update self-hosting.md documentation for running with Prometheus (#6052)

* Update documentation for running with Prometheus

There's two environment variables that need to be set in order to use Prometheus and the /metrics endpoint.

* Missing s

* Update doc/self-hosting.md

Co-authored-by: Caleb Cartwright <57164230d45de9cae60a8d520caf70bd9319ca42@users.noreply.github.com>

Co-authored-by: Caleb Cartwright <57164230d45de9cae60a8d520caf70bd9319ca42@users.noreply.github.com>
Co-authored-by: repo-ranger[bot] <4f5691a0f42c9db700937238e633bc238b94b55c@users.noreply.github.com>
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