Fix Typographical Errors in Comments and Documentation

[leopardracer]

Description:
This pull request corrects minor typographical errors in comments and documentation across the codebase. Specifically:

• In helix-core/src/movement.rs, the word "traversing" was corrected in a comment.
• In helix-stdx/src/env.rs, the word "environment" was corrected in the documentation comment.

These changes improve code readability and maintain documentation accuracy. No functional code changes were made.

[leopardracer]

@icorbrey ready to merge?

[icorbrey]

I personally think so but I don't have write access

[the-mikedavis]

Generally we don't accept typo fixes or style changes to the Rust code since it creates unnecessary conflicts for open PRs and makes the blame harder to follow