Add: Zero Cost Abstractions

Relevant links:

- https://blog.rust-lang.org/2015/05/11/traits.html
- https://boats.gitlab.io/blog/post/zero-cost-abstractions/

Read the two linked articles about Rust traits and zero-cost abstractions, then inspect the repository's existing dictionary entries to find the expected format and location. The issue does not name a file or test; done should be a repository entry explaining the term and linking the relevant references.

Written by the indexing model from the issue text.