Code made compatible with Airbnb style guide

[0o001]

Add arrays bracket newline https://github.com/airbnb/javascript#arrays--bracket-newline

Add array destructuring https://github.com/airbnb/javascript#destructuring--array

And severities array put inside the getSeverity function

[0o001]

What is enforcing this change?

I wanted to align the used codes with the format recommended in Airbnb's own style guide.

[ljharb]

Right, but our own eslint rules in this project should be enforcing that, rather than doing it manually.