Formatter: Fix syntax error location in notebooks

[MichaReiser]

Summary

Fixes #16476
fixes: #11453

We format notebooks cell by cell. That means, that offsets in parse errors are relative
to the cell and not the entire document. We didn't account for this fact
when emitting syntax errors for notebooks in the formatter.

This PR ensures that we correctly offset parse errors by the cell location.

Test Plan

Added test (it panicked before)

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

Formatter (stable)

✅ ecosystem check detected no format changes.

Formatter (preview)

✅ ecosystem check detected no format changes.

[dhruvmanila]

Thank you! I'll close #11456 one out then.