fix(format-rust): use null-delimited git ls-files to prevent quote decoding errors

[tecnolgd]

Summary

Fixed an issue in tools/format-rust.py where line-delimited git ls-files parsing dropped or failed on file paths containing spaces or non-ASCII (Unicode) characters. Switched to null-delimited processing (-z) to parse file paths safely.

Motivation

Non-ASCII and space-separated file names caused git to wrap paths in double quotes in standard line-delimited outputs, resulting in parsing failures and silent omissions. This update aligns the utility script with robust null-delimited path handling.

Closes #892

Target and compatibility impact

Python tooling script(tools/format-rust.py) only. No changes to compiler targets, ABIs, or language contracts.

Validation

• Python compile Check: python3 -m py_compile tools/format-rust.py

• Corpus Verification: python3 tools/check_wave_corpus.py

• Manual testing: Created local test files containing spaces and non-ASCII Unicode characters (e.g., café.rs, café with spaces.rs).

  Verified that the original line-delimited .splitlines() implementation silently dropped these entries (discovering 206 files), whereas the new null-delimited -z implementation correctly identifies and processes all 208 files without truncation or quoting corruption.

Checklist

• Commits include a DCO Signed-off-by line.
• Tests cover new behavior or the PR explains why no test is needed.
• User-facing changes include documentation or diagnostics updates.
• The change preserves the license boundary between the compiler and std/.

[LunaStev]

LGTM thanks