Mention getting mesa to enable Vulkan for more useful WSL setup

I'd probably mention something about getting an up to date version of mesa (eg. through the kisak ppa for ubuntu) to run bevy on vulkan instead of gl (since bevy's GL targets GLES 3.0/webgl2 which is extremely limiting).

_Originally posted by @Elabajaba in https://github.com/bevyengine/bevy/issues/9842#issuecomment-1726514866_

Start by reviewing the WSL setup guidance and the referenced discussion in issue 9842. Update the relevant documentation to mention obtaining an up-to-date Mesa version, such as through the Kisak PPA on Ubuntu, and explain using Vulkan instead of GL for Bevy; the documentation should clearly describe the resulting setup and its rationale.

Written by the indexing model from the issue text.