Update: 0206-reverse-linked-list.rs

[JustLeif]

Fix typo / small syntax improvement

The current state of this solution does not compile.

• File(s) Modified: 0206-reverse-linked-list.rs
• Language(s) Used: Rust
• Submission URL: https://leetcode.com/problems/reverse-linked-list/submissions/1130832831/

Important

Please make sure the file name is lowercase and a duplicate file does not already exist before merging.