--no-modify-path has been deprecated

I checked `--help` prior to installing and ran the install.sh script with the `--no-modify-path` flag which produced the following warning about that flag being deprecated:
```
$ ./install.sh -v --no-modify-path
--no-modify-path has been deprecated; please set UV_NO_MODIFY_PATH=1 in the environment
downloading uv 0.5.25 aarch64-apple-darwin
from https://github.com/astral-sh/uv/releases/download/0.5.25/uv-aarch64-apple-darwin.tar.gz
to /var/folders/j4/938xc6yx00v6kfjv8nzfb0v80000gs/T/tmp.p5NwOasNJk/input.tar.gz
no checksums to verify
installing to /path/to/.local/bin
uv
uvx
everything's installed!
```

Should the `--help` contents be updated to reflect the change?

**Platform**
macOS 14.4 arm64

**Version**
0.5.25

**Python version**
Python 3.13.1

Edit:
It was requested that I move this bug report here.
Original: https://github.com/astral-sh/uv/issues/11057

Start with install.sh and inspect the --help output alongside the handling of --no-modify-path. Confirm whether the help text still advertises the deprecated flag, then verify the updated help and installation behavior on the documented macOS setup.

Written by the indexing model from the issue text.