doc: fix typos in async_context.md

PR-URL: #47155
Reviewed-By: Debadree Chatterjee <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Deokjin Kim <[email protected]>
Reviewed-By: Harshitha K P <[email protected]>
Reviewed-By: Chengzhong Wu <[email protected]>

doc/api/async_context.md

@@ -167,7 +167,7 @@ calls the function passed to it within the captured context.
 
 ```js
 const asyncLocalStorage = new AsyncLocalStorage();
-const runInAsyncScope = asyncLocalStorage.run(123, () => asyncLocalStorage.snapshot());
+const runInAsyncScope = asyncLocalStorage.run(123, () => AsyncLocalStorage.snapshot());
 const result = asyncLocalStorage.run(321, () => runInAsyncScope(() => asyncLocalStorage.getStore()));
 console.log(result);  // returns 123
 ```