zed: Reduce number of rayon threads, spawn with bigger stacks (#41812)

We already do this for the cli and remote server but forgot to do so for
the main binary

Release Notes:

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

Cargo.lock

@@ -21233,6 +21233,7 @@ dependencies = [
  "project_symbols",
  "prompt_store",
  "proto",
+ "rayon",
  "recent_projects",
  "release_channel",
  "remote",

crates/zed/Cargo.toml

@@ -73,6 +73,7 @@ gpui = { workspace = true, features = [
     "windows-manifest",
 ] }
 gpui_tokio.workspace = true
+rayon.workspace = true
 
 edit_prediction_button.workspace = true
 http_client.workspace = true

crates/zed/src/main.rs

@@ -257,6 +257,13 @@ pub fn main() {
         return;
     }
 
+    rayon::ThreadPoolBuilder::new()
+        .num_threads(4)
+        .stack_size(10 * 1024 * 1024)
+        .thread_name(|ix| format!("RayonWorker{}", ix))
+        .build_global()
+        .unwrap();
+
     log::info!(
         "========== starting zed version {}, sha {} ==========",
         app_version,