Closes #49565

Before you mark this PR as ready for review, make sure that you have:
- [x] Added a solid test coverage and/or screenshots from doing manual
testing
- [x] Done a self-review taking into account security and performance
aspects
- [ ] Aligned any UI changes with the [UI

checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)

Screenshots
Before:
<img width="1509" height="726" alt="image"
src="https://github.com/user-attachments/assets/4931262a-e243-4e54-8ba8-f5fd13ec7bff"
/>



After:
<img width="1284" height="611" alt="image"
src="https://github.com/user-attachments/assets/0466cab6-d303-484c-a22b-4c168d21cec6"
/>
<img width="1284" height="611" alt="image"
src="https://github.com/user-attachments/assets/d6bce35b-e599-42da-9c4d-214e490677d5"
/>


Release Notes:

- Fixed edit predictions polluting the completions menu with unrelated
snippets (e.g. Unicode symbols) when
`show_in_completions_menu` is disabled

---------

Co-authored-by: Ben Kunkle <ben.kunkle@gmail.com>