[DOC]: Expand .devcontainer/README.md with instructions for WSL

[jrhemstad]

Is this a duplicate?

• I confirmed there appear to be no duplicate issues for this bug and that I agree to the Code of Conduct

Is this for new documentation, or an update to existing docs?

New

Describe the incorrect/future/missing documentation

As a Windows developer that would like to leverage CCCL's Linux devcontainers with WSL, I'd like to have clear documentation on how to get started. We should defer to our Linux devcontainer documentation as much as possible and just provide guidance on anything unique to WSL.

These instructions should:

• List any prerequisites
• Provide a reference to how to install the appropriate version of WSL
• Provide instruction on how to use VSCode w/ devcontainer running in WSL

The end goal is that a technically competent person who may have never used WSL or VScode before should be able to follow these instructions to the point where they can build and run CCCL's tests on a Windows machine in WSL.

If this is a correction, please provide a link to the incorrect documentation. If this is a new documentation request, please link to where you have looked.

No response

[jrhemstad]

@miscco @allisonvacanti @wmaxey since all of you work natively in Windows and use WSL with our devcontainers already, would one of you be willing to take this on?

[jrhemstad]

@gonidelis will be working on this.