`--sort-reexports` hardcodes LF line endings regardless of platform

Hi, it's me again about --sort-reexports (sorry).

I saw that PR #2605 resolving my issue #2578 was merged and tried it out from GitHub directly (because I'm impatient) and to my delight, it works! Thank you for that!

However, now my editor (PyCharm) as well as my pre-commit config for mixed-line-endings seemed to fight with every run of isort with --sort-reexports, causing lots of files to be rewritten by mixed-line-endings (which makes sure files have a consistent line ending).

I checked what was going on and apparently isort is currently hardcoding \n for the exports. You can see the effect in the following file, named repro.py:

from .somewhere import FirstClass, SecondClass

__all__ = (
    "FirstClass",
    "SecondClass",
)

On my Windows machine in Notepad++ with invisible chars made visible, the before & after looks like this: (apologies for screenshots of code but I thought this was the most visible way to convey this)

Before	After running isort repro.py --sort-reexports --profile black

To be clear, it does correctly sort the exports and it does correctly keep the trailing comma, my issue report is just about the fact that it produces mixed line endings in the file.

Tested with pip install git+https://github.com/PyCQA/isort@f00e091982aa174f1700beab29c94512de9d64fd (f00e091982aa174f1700beab29c94512de9d64fd, which was the most recent commit on main at the time of me testing this out)

• Windows 11
• Python 3.14.7