Improve LSP tasks ergonomics (#31551)

* stopped fetching LSP tasks for too long (but still use the hardcoded
value for the time being — the LSP tasks settings part is a simple bool
key and it's not very simple to fit in another value there)

* introduced `prefer_lsp` language task settings value, to control
whether in the gutter/modal/both/none LSP tasks are shown exclusively,
if possible

Release Notes:

- Added a way to prefer LSP tasks over Zed tasks

crates/editor/src/editor.rs

@@ -1670,6 +1670,13 @@ impl Editor {
                             editor
                                 .refresh_inlay_hints(InlayHintRefreshReason::RefreshRequested, cx);
                         }
+                        project::Event::LanguageServerAdded(..)
+                        | project::Event::LanguageServerRemoved(..) => {
+                            if editor.tasks_update_task.is_none() {
+                                editor.tasks_update_task =
+                                    Some(editor.refresh_runnables(window, cx));
+                            }
+                        }
                         project::Event::SnippetEdit(id, snippet_edits) => {
                             if let Some(buffer) = editor.buffer.read(cx).buffer(*id) {
                                 let focus_handle = editor.focus_handle(cx);
@@ -13543,6 +13550,7 @@ impl Editor {
         }
         let project = self.project.as_ref().map(Entity::downgrade);
         let task_sources = self.lsp_task_sources(cx);
+        let multi_buffer = self.buffer.downgrade();
         cx.spawn_in(window, async move |editor, cx| {
             cx.background_executor().timer(UPDATE_DEBOUNCE).await;
             let Some(project) = project.and_then(|p| p.upgrade()) else {
@@ -13626,7 +13634,19 @@ impl Editor {
                 return;
             };
 
-            let rows = Self::runnable_rows(project, display_snapshot, new_rows, cx.clone());
+            let Ok(prefer_lsp) = multi_buffer.update(cx, |buffer, cx| {
+                buffer.language_settings(cx).tasks.prefer_lsp
+            }) else {
+                return;
+            };
+
+            let rows = Self::runnable_rows(
+                project,
+                display_snapshot,
+                prefer_lsp && !lsp_tasks_by_rows.is_empty(),
+                new_rows,
+                cx.clone(),
+            );
             editor
                 .update(cx, |editor, _| {
                     editor.clear_tasks();
@@ -13654,15 +13674,21 @@ impl Editor {
     fn runnable_rows(
         project: Entity<Project>,
         snapshot: DisplaySnapshot,
+        prefer_lsp: bool,
         runnable_ranges: Vec<RunnableRange>,
         mut cx: AsyncWindowContext,
     ) -> Vec<((BufferId, BufferRow), RunnableTasks)> {
         runnable_ranges
             .into_iter()
             .filter_map(|mut runnable| {
-                let tasks = cx
+                let mut tasks = cx
                     .update(|_, cx| Self::templates_with_tags(&project, &mut runnable.runnable, cx))
                     .ok()?;
+                if prefer_lsp {
+                    tasks.retain(|(task_kind, _)| {
+                        !matches!(task_kind, TaskSourceKind::Language { .. })
+                    });
+                }
                 if tasks.is_empty() {
                     return None;
                 }