The Dockerfile code example was broken for me - this PR fixes this
error.

## Summary

Closes #1349.

Using `rye toolchain remove` now lists all tools that use a specific
toolchain.

This eliminates the Whac-a-Mole game of reiterating through the `rye
toolchain remove blabla` command in order to actually remove it.

## Example Usage

```bash
$ rye install black --quiet --python 3.11.7
$ rye toolchain remove 3.11.7
error: toolchain cpython@3.11.7 is still in use by tool black
$ rye install ruff --quiet --python 3.11.7
$ rye toolchain remove 3.11.7
error: toolchain cpython@3.11.7 is still in use by tools: black, ruff
```

_(Side note: Rust isn't my main d2d language, feel free to comment on
coding style and unidiomatic code)_

Explanations:

* `.*?$` is the same as `.*`: Being lazy at the end is the same as being
greedy.
* `[^\-]` is the same as `[^-]`: The `-` here cannot be considered a
part of a range.
* The dot in `user.(name|email)` acts as a metacharacter.
* `(?:(via)|(?:via (.*?))|(?: (.*?)))$` is equivalent to `(?:via$|via
(.*)| (.*))`.
Consequently, a line below was changed from `.get(2).or_else(||
m.get(3))` to `.get(1).or_else(|| m.get(2))`.

Previously, in *some* situations, `rye pin <pythonversion>; rye list`
could lead to rye deleting the existing virtualenv.

I suggest that `rye list` should be an interrogator and never modify any
project. With this change, it lists its own and non-rye virtualenvs
(same behaviour as uv pip freeze) but should never create, recreate or
overwrite environments (own or non-rye).

Fixes #1352

- Synced latest UV releases

<sup>Auto-generated by
[sync-uv-releases.yml](https://github.com/astral-sh/rye/blob/main/.github/workflows/sync-uv-releases.yml)</sup>

Co-authored-by: mitsuhiko <7396+mitsuhiko@users.noreply.github.com>

- Synced latest Python releases

<sup>Auto-generated by
[sync-python-releases.yml](https://github.com/astral-sh/rye/blob/main/.github/workflows/sync-python-releases.yml)</sup>

---------

Co-authored-by: mitsuhiko <7396+mitsuhiko@users.noreply.github.com>
Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>

- Synced latest UV releases

<sup>Auto-generated by
[sync-uv-releases.yml](https://github.com/astral-sh/rye/blob/main/.github/workflows/sync-uv-releases.yml)</sup>

Co-authored-by: mitsuhiko <7396+mitsuhiko@users.noreply.github.com>

- Synced latest UV releases

<sup>Auto-generated by
[sync-uv-releases.yml](https://github.com/astral-sh/rye/blob/main/.github/workflows/sync-uv-releases.yml)</sup>

Co-authored-by: mitsuhiko <7396+mitsuhiko@users.noreply.github.com>