Pre-initialize global rayon threadpool (#41226)

We only use it a handful of times and the default amount of threads
(logical cpu core number) its spawns is overkill for this. This also
gives the threads names oppose to being labeled `<unknown>`

Release Notes:

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

crates/editor/src/display_map.rs

@@ -751,6 +751,7 @@ pub struct DisplaySnapshot {
     diagnostics_max_severity: DiagnosticSeverity,
     pub(crate) fold_placeholder: FoldPlaceholder,
 }
+
 impl DisplaySnapshot {
     pub fn wrap_snapshot(&self) -> &WrapSnapshot {
         &self.block_snapshot.wrap_snapshot
@@ -1408,6 +1409,14 @@ impl DisplaySnapshot {
     }
 }
 
+impl std::ops::Deref for DisplaySnapshot {
+    type Target = BlockSnapshot;
+
+    fn deref(&self) -> &Self::Target {
+        &self.block_snapshot
+    }
+}
+
 #[derive(Copy, Clone, Default, Eq, Ord, PartialOrd, PartialEq)]
 pub struct DisplayPoint(BlockPoint);