project: Fine-grained language server management (#24038)

Closes #ISSUE
https://github.com/zed-industries/zed/pull/23804
Release Notes:

- Improved detection of project roots for use by language servers.

Closes #ISSUE

Release Notes:

- N/A *or* Added/Fixed/Improved ...

---------

Co-authored-by: smit <0xtimsb@gmail.com>
Co-authored-by: Henrikh Kantuni <henrikh.kantuni@gmail.com>
Co-authored-by: Caleb! <48127194+kaf-lamed-beyt@users.noreply.github.com>
Co-authored-by: Marshall Bowers <git@maxdeviant.com>
Co-authored-by: Kirill Bulatov <kirill@zed.dev>
Co-authored-by: Agus Zubiaga <agus@zed.dev>
Co-authored-by: Danilo <danilo@zed.dev>
Co-authored-by: Nate Butler <iamnbutler@gmail.com>

crates/outline/src/outline.rs

@@ -370,6 +370,7 @@ mod tests {
     use language::{Language, LanguageConfig, LanguageMatcher};
     use project::{FakeFs, Project};
     use serde_json::json;
+    use util::path;
     use workspace::{AppState, Workspace};
 
     #[gpui::test]
@@ -377,7 +378,7 @@ mod tests {
         init_test(cx);
         let fs = FakeFs::new(cx.executor());
         fs.insert_tree(
-            "/dir",
+            path!("/dir"),
             json!({
                 "a.rs": indoc!{"
                     struct SingleLine; // display line 0
@@ -391,7 +392,7 @@ mod tests {
         )
         .await;
 
-        let project = Project::test(fs, ["/dir".as_ref()], cx).await;
+        let project = Project::test(fs, [path!("/dir").as_ref()], cx).await;
         project.read_with(cx, |project, _| project.languages().add(rust_lang()));
 
         let (workspace, cx) =
@@ -402,7 +403,9 @@ mod tests {
             })
         });
         let _buffer = project
-            .update(cx, |project, cx| project.open_local_buffer("/dir/a.rs", cx))
+            .update(cx, |project, cx| {
+                project.open_local_buffer(path!("/dir/a.rs"), cx)
+            })
             .await
             .unwrap();
         let editor = workspace