fix: file path containing spaces in rufo command not handled properly

[taham8875]

Hello maintainers,

I've encountered an issue where executing the rufo command in the vscode-rufo extension failed when the file path contained spaces. For instance, a file was located at ~/Documents/GitHub/problem-solving/1. Two Sum/main.rb, and running rufo directly on this file path broke due to misinterpretation by the command line.

To resolve this issue, I've made a simple adjustment in the code. Specifically, I added single quotes around the file path parameter in the rufo command, ensuring that the command line interprets it as a single entity rather than separate parameters.

This change fixes the issue #24

Thank you for considering this pull request. Let me know if you have any questions.

Best regards