check-case-conflict errors on any file on macOS

[muzimuzhi]

$ git init test-check-case-conflict && cd test-check-case-conflict
$ touch a.txt
$ git add a.txt
$ hk util check-case-conflict a.txt
Case conflict:
  a.txt
  a.txt
Error: Case conflicts found in file paths

Location:
    src/cli/util/check_case_conflict.rs:31:24

$ hk --version
hk 1.34.0

$ git -P config get core.ignorecase
true

I'm on macOS 14.8.2 x86_64.

[muzimuzhi]

Fixed in hk 1.36.0, by

• Deduplicate files in check-case-conflict to prevent false positives #678