## Summary
I always found it odd that we had to pass this in, since it's really
higher-level context for the error. The awkwardness is further evidenced
by the fact that we pass in fake values everywhere (even outside of
tests). The source path isn't actually used to display the error; it's
only accessed elsewhere to _re-display_ the error in certain cases. This
PR modifies to instead pass the path directly in those cases.
Improves the `ruff_parse_simple` fuzz harness by adding checks for
parsed locations to ensure they all lie on UTF-8 character boundaries.
This will allow for faster identification of issues like #5004.
This also adds additional details for Apple M1 users and clarifies the
importance of using `init-fuzzer.sh` (thanks for the feedback,
@jasikpark 🙂).
