docs: Add pyreqwest_impersonate to example projects

[deedy5]

Add pyreqwest_impersonate to example projects

[deedy5]

https://github.com/PyO3/pyo3/actions/runs/8833222548/job/24252063805?pr=4123

nox > lychee --include-fragments /home/runner/work/pyo3/pyo3/guide/src --remap 'file:///home/runner/work/pyo3/pyo3/guide/src/([^/]*/)*?%7B%7B#PYO3_DOCS_URL}} file:///home/runner/work/pyo3/pyo3/target/doc' --remap '%7B%7B#PYO3_DOCS_VERSION}} latest'
  Issues found in 1 input. Find details below.
  
  [/home/runner/work/pyo3/pyo3/guide/src/parallelism.md]:
  ✗ [403] https://stackoverflow.com/questions/868568/ | Failed: Network error: Forbidden
  
  🔍 411 Total (in 21s) ✅ 410 OK 🚫 1 Error
  nox > Command lychee --include-fragments /home/runner/work/pyo3/pyo3/guide/src --remap 'file:///home/runner/work/pyo3/pyo3/guide/src/([^/]*/)*?%7B%7B#PYO3_DOCS_URL}} file:///home/runner/work/pyo3/pyo3/target/doc' --remap '%7B%7B#PYO3_DOCS_VERSION}} latest' failed with exit code 2
Error: `lychee --include-fragments /home/runner/work/pyo3/pyo3/guide/src --remap file:///home/runner/work/pyo3/pyo3/guide/src/([^/]*/)*?%7B%7B#PYO3_DOCS_URL}} file:///home/runner/work/pyo3/pyo3/target/doc --remap %7B%7B#PYO3_DOCS_VERSION}} latest` failed
nox > Session check-guide failed.
Error: Process completed with exit code 1.

I don't understand the error, I didn't change anything there.

[davidhewitt]

Thanks!

I think the CI failure was just flakiness.