Support tasks from rust-analyzer (#28359)

(and any other LSP server in theory, if it exposes any LSP-ext endpoint
for the same)

Closes https://github.com/zed-industries/zed/issues/16160

* adds a way to disable tree-sitter tasks (the ones from the plugins,
enabled by default) with
```json5
"languages": {
  "Rust": "tasks": {
      "enabled": false
    }
  }
}
```
language settings

* adds a way to disable LSP tasks (the ones from the rust-analyzer
language server, enabled by default) with
```json5
"lsp": {
  "rust-analyzer": {
    "enable_lsp_tasks": false,
  }
}
```

* adds rust-analyzer tasks into tasks modal and gutter:

<img width="1728" alt="modal"
src="https://github.com/user-attachments/assets/22b9cee1-4ffb-4c9e-b1f1-d01e80e72508"
/>

<img width="396" alt="gutter"
src="https://github.com/user-attachments/assets/bd818079-e247-4332-bdb5-1b7cb1cce768"
/>


Release Notes:

- Added tasks from rust-analyzer

crates/tasks_ui/src/tasks_ui.rs

@@ -1,6 +1,6 @@
-use std::collections::HashMap;
 use std::path::Path;
 
+use collections::HashMap;
 use debugger_ui::Start;
 use editor::Editor;
 use feature_flags::{Debugger, FeatureFlagViewExt};
@@ -313,6 +313,17 @@ fn task_contexts(workspace: &Workspace, window: &mut Window, cx: &mut App) -> Ta
         })
     });
 
+    let lsp_task_sources = active_editor
+        .as_ref()
+        .map(|active_editor| active_editor.update(cx, |editor, cx| editor.lsp_task_sources(cx)))
+        .unwrap_or_default();
+
+    let latest_selection = active_editor.as_ref().map(|active_editor| {
+        active_editor.update(cx, |editor, _| {
+            editor.selections.newest_anchor().head().text_anchor
+        })
+    });
+
     let mut worktree_abs_paths = workspace
         .worktrees(cx)
         .filter(|worktree| is_visible_directory(worktree, cx))
@@ -325,6 +336,9 @@ fn task_contexts(workspace: &Workspace, window: &mut Window, cx: &mut App) -> Ta
     cx.background_spawn(async move {
         let mut task_contexts = TaskContexts::default();
 
+        task_contexts.lsp_task_sources = lsp_task_sources;
+        task_contexts.latest_selection = latest_selection;
+
         if let Some(editor_context_task) = editor_context_task {
             if let Some(editor_context) = editor_context_task.await {
                 task_contexts.active_item_context =