Update advanced docs (WSL)

What does this merge request do and why?

Update advanced docs (WSL)

They described a shell command but omitted one parameter (the version)

    --set-version <Distro> <Version>
        Changes the version of the specified distribution.

This avoids the following error:

PS> wsl --set-version Ubuntu-22.04
A version number could not be parsed.
Error code: Wsl/ERROR_VERSION_PARSE_ERROR

The following does work:

PS> wsl --set-version Ubuntu-22.04 2
For information on key differences with WSL 2 please visit https://aka.ms/wsl2
Conversion in progress, this may take a few minutes.
The distribution is already the requested version.
Error code: Wsl/Service/WSL_E_VM_MODE_INVALID_STATE

(You can ignore the error code, I am already on version 2)

How to set up and validate locally

You can run the following command: wsl --set-version Ubuntu-22.04 2 (or variants depending on which OS you use for WSL), provided you are on a Windows machine.

Impacted categories

The following categories relate to this merge request:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Merge request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise an issue to follow-up.
• Documentation added/updated, if needed.
• Announcement added, if change is notable.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.