Improve help text with clearer message for --terminate option

**Is your feature request related to a problem? Please describe.**
the term "terminate" can be incorrectly translated depending on languages.

**Describe the solution you'd like**
The current help text could be improved by adding context with `(shutdown)`

from:

```
--terminate, -t
Terminates the specified distribution.
```

to:

```

--terminate, -t
Terminates (shutdown) the specified distribution.
```

**Describe alternatives you've considered**
nothing

**Additional context**
`(shutdown)` might also be the wrong context since there is no shutdown process executed. Instead `--terminate` **kills** a Windows PID? or what better term or short phrase added that could be used as additional context to describe what really happens with this option ? If a user opts to NOT use systemd, then would the chosen term or short phrase have a slightly different meaning here? Somethings to consider in this help text improvement issue.

Start by locating the WSL CLI help-text definition for --terminate and verify what the option actually does, including whether systemd changes that behavior. Done means agreeing on a short, accurate replacement for the current description and updating the corresponding help text.

Written by the indexing model from the issue text.