Update documentation on Starlette website

[antonpirker]

Problem Statement

Tom Christie (creator of Starlette) suggested, that we submit a PR for updating their documentation.

See this discussion: Kludex/starlette#1787 (comment)

Solution Brainstorm

Create two PRs, one for each suggested topic by Tom.
Link back to the Starlette guide on Sentry: https://docs.sentry.io/platforms/python/guides/starlette/