Add --check to built-in hooks without a read-only mode

[pygarap]

Proposal

Please add a hook-level --check argument to the builtin hooks without a read-only mode, enabling CI and local validation without applying changes.

Scope

Add --check to these five hooks:

• trailing-whitespace (Trims trailing whitespace.)
• end-of-file-fixer (Ensures files are empty or end with exactly one newline.)
• file-contents-sorter (Sorts lines in specified files.)
• requirements-txt-fixer (Sorts entries in requirements.txt.)
• fix-byte-order-marker (Removes a UTF-8 byte order marker.)

Exclude hooks with existing read-only modes:

• pretty-format-json (Checks without modifying files when --autofix is omitted.)
• mixed-line-ending (Checks without modifying files with --fix=no.)

All other built-in hooks are read-only and remain unchanged.

Behavior

• With --check, evaluate fixes using the configured options and only read access, without changing workspace state, even temporarily.
• Report files that would change and exit nonzero when fixes are needed, or errors occur; otherwise, exit zero.
• Preserve existing behavior when --check is omitted.

Usage

Example .pre-commit-config.yaml combining the new flag with existing read-only modes:

repos:
  - repo: builtin
    hooks:
      - id: trailing-whitespace
        args: [--check]
      - id: end-of-file-fixer
        args: [--check]
      - id: file-contents-sorter
        files: '^sorted-list\.txt$'
        args: [--check]
      - id: requirements-txt-fixer
        args: [--check]
      - id: fix-byte-order-marker
        args: [--check]
      - id: pretty-format-json
      - id: mixed-line-ending
        args: [--fix=no]

$ prek run --all-files

[j178]

Thanks, make sense to me.