Show per-cell diffs when analyzing notebooks over stdin

[charliermarsh]

Summary

The implementation here differs from the non-stdin version -- this is now more consistent.

Test Plan

❯ cat Untitled.ipynb | cargo run -p ruff_cli -- check --stdin-filename Untitled.ipynb --diff -n
    Finished dev [unoptimized + debuginfo] target(s) in 0.11s
     Running `target/debug/ruff check --stdin-filename Untitled.ipynb --diff -n`
--- Untitled.ipynb:cell 2
+++ Untitled.ipynb:cell 2
@@ -1 +0,0 @@
-import os
--- Untitled.ipynb:cell 4
+++ Untitled.ipynb:cell 4
@@ -1 +0,0 @@
-import sys

[codspeed-hq]

CodSpeed Performance Report

Merging #7789 will improve performances by 2.58%

_{Comparing charlie/diff (f35e4f1) with main (600471e)}

Summary

⚡ 1 improvements
✅ 24 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	charlie/diff	Change
⚡	linter/default-rules[pydantic/types.py]	39 ms	38 ms	+2.58%

[dhruvmanila]

Thanks!

[dhruvmanila]

nit: This is repeated for stdout as well but I think the only difference is that the path is optional. Could we combine them under SourceKind in the same way as done in FixMode::Apply? That would avoid code duplication.

[charliermarsh]

I'll take a look at this in a follow-up as its leading me to want to make some other changes.

[dhruvmanila]

Do you think a default value of - (or stdin / STDIN) would be good to show as the filename for stdin? I think we do that in other places. So, the output would something like:

-:cell 0:
...

-:cell 2:
...

[charliermarsh]

Hmm, we don't do this in the Python case, so I'll leave it for now.

[github-actions]

PR Check Results

Ecosystem

✅ ecosystem check detected no changes.