test(repo): show complete incremental blame path failures

The `test (windows, 3.15)` and `test (windows, 3.12, gix)` CI jobs
fail the new historical-path regression for its combined control-character
filename under both `core.quotePath` settings. Their assertion messages
truncate the actual and expected entries and omit the full diff, leaving
the precise filename mismatch unavailable in the job logs.

Set `TestCase.maxDiff` to `None` in this regression so CI reports the
complete values. This preserves every assertion and the implementation;
it provides the evidence needed to distinguish fixture handling from a
parser defect before changing behavior.

The focused regression passes locally on the CLI and Gix backends with
all sixteen filename/quoting subcases. Ruff lint and formatting checks
and `git diff --check` pass.

Author: codex

test/test_repo.py

@@ -756,6 +756,7 @@ def test_blame_incremental(self, git):
             )
 
     def test_blame_incremental_preserves_historical_paths(self):
+        self.maxDiff = None
         paths = (
             b"plain.txt",
             b" spaced name.txt ",