Fix more bugs in files (#16241)

Fixes:
- [x] an issue where directories would only match by prefix, causing
both a directory and a file to be matched if in the same directory
- [x] An issue where you could not continue a file completion when
selecting a directory, as `tab` on a file would always run the command.
This effectively disabled directory sub queries.
- [x] Inconsistent rendering of files and directories in the slash
command

Release Notes:

- N/A

---------

Co-authored-by: max <max@zed.dev>

crates/project/src/project.rs

@@ -12,6 +12,7 @@ pub mod worktree_store;
 
 #[cfg(test)]
 mod project_tests;
+
 pub mod search_history;
 mod yarn;