timers: modified comment to try/finally

Replaced try/catch with try/finally in comments, line 744.

Fixes: nodejs#14308

Author: Moniarchy

lib/timers.js

@@ -741,7 +741,7 @@ function tryOnImmediate(immediate, oldTail) {
   var threw = true;
   emitBefore(immediate[async_id_symbol], immediate[trigger_id_symbol]);
   try {
-    // make the actual call outside the try/catch to allow it to be optimized
+    // make the actual call outside the try/finally to allow it to be optimized
     runCallback(immediate);
     threw = false;
   } finally {