WSL path not always starting with /mnt

[MrMarble]

Description

The windows filesystem inside wsl is not always mounted on /mnt, as it can be changed by the user. see the key root on the automount section in the wsl docs

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Issues Fixed or Closed by This PR

• [Bug] Windows filesystem is not always mounted on /mnt #9593

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[stale]

Thank you for your contribution!
This pull request has been automatically marked as stale because it has not had activity in the last 45 days. It will be closed in 30 days if no further activity occurs. Please feel free to give a status update now, or re-open when it's ready.
For maintainers: Please label with awaiting review, breaking_change, in progress, or on hold to prevent the issue from being re-flagged.

[tzarc]

For some reason this script's mode was changed from 755 to 644 (i.e. no longer executable) -- that'll need to be fixed too.

[stale]

Thank you for your contribution!
This pull request has been automatically marked as stale because it has not had activity in the last 45 days. It will be closed in 30 days if no further activity occurs. Please feel free to give a status update now, or re-open when it's ready.
For maintainers: Please label with awaiting review, breaking_change, in progress, or on hold to prevent the issue from being re-flagged.

[fauxpark]

Thanks for your contribution!

I'm closing this PR as it has been rendered obsolete by the removal of wsl_install.sh in #10593 - installation under WSL is now treated as a normal Linux install, with a notice at the end that you should install the QMK Toolbox and map the WSL filesystem to a network drive in order to flash. This is hopefully a temporary measure, until WSL gets proper USB support.