docs: quote pip extras install examples

[nyxst4ck]

Summary

• Quote pip install examples that include extras.

Why

• Shells such as zsh can expand unquoted bracket expressions before pip receives them.

Scope

• Files changed:
• mlsysim/tutorial/prerequisites.md
• This does not change dependencies or runtime behavior.

Testing

• git diff --check

Maintainer Fit

• Small install-command correctness fix.
• Duplicate PR search terms checked: quote pip extras, quote optional dependency, zsh pip install extras, pip extras install examples

[github-actions]

Thanks @nyxst4ck! 🎉

I added @nyxst4ck to mlsysim for: doc.

The contributor tables are now handled directly by this workflow; no follow-up command is needed.