Recent Rust versions give "this error originates in a macro" more
frequently, and on one occasion removed the "outside of the current
crate" remark.
This acknowledges the change in the stderr of the test cases, given the
information makes sense and does not deteriorate user experience.
This fixes regressions in the CI suite that fail otherwise unrelated
pull requests, probably due to nowadays stricter clippy errors (`cargo
+nightly clippy` previously failed with 'error[E0601]: `main` function
not found in crate `typed_html_tests`').