…ment setup guide (cvat-ai#8313)

- This commit adds a step to the CVAT development setup guide for users working with WSL (Windows Subsystem for Linux). The added instruction guides users to install the VS Code extension for WSL, ensuring that Visual Studio Code opens correctly inside the WSL environment.

- This change addresses an issue where users might encounter a 'DEBUG STOPPED' error if the extension is not installed, improving the overall setup experience.

- Related to issue cvat-ai#8313.

Fixed the issue of lines exceeding the 120-character limit by splitting them into separate lines. Added a step to install the VS Code WSL extension in the development environment setup documentation.

Co-authored-by: Andrey Zhavoronkov <andrey@cvat.ai>