Improve Autocomplete Suggestions

[smitbarmase]

Summary

This is the parent issue to track all bugs related to autocomplete suggestions in the editor. It only includes issues with filter/sort logic bugs, not language-specific ones.

1. Spaces break query matching: git ^ shows no suggestions while git^ correctly shows git commit, etc.
2. Fullstop/periods break word boundaries: ../internal/format.^ doesn't properly recognize format.ts as a match.
3. Only matches word prefixes: env^ fails to suggest load_direnv as it only matches prefixes of words.
4. Sorting priority: px-4^ shows scroll-px-4 before the exact match px-4.
5. Namespace operators break completion: project_panel::toggle^ doesn't suggest project_panel::ToggleFocus.

Zed Version and System Specs

Zed: v0.179.0 (Zed Nightly a0f995d)
OS: macOS 15.3.2
Memory: 64 GiB
Architecture: aarch64