Eagerly update worktree entries when saving

Don't use ModelHandles for storing Files.

Co-Authored-By: Max Brunsfeld <maxbrunsfeld@gmail.com>

zed/src/worktree/fuzzy.rs

@@ -619,6 +619,7 @@ mod tests {
                 ignores: Default::default(),
                 entries: Default::default(),
                 root_name: Default::default(),
+                root_char_bag: Default::default(),
             },
             false,
             path_entries.into_iter(),