doc: remove buffered flag from performance hooks examples

PR-URL: #52607
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: pavel-romanov8

doc/api/perf_hooks.md

@@ -1849,7 +1849,7 @@ const obs = new PerformanceObserver((list, observer) => {
   performance.clearMeasures();
   observer.disconnect();
 });
-obs.observe({ entryTypes: ['measure'], buffered: true });
+obs.observe({ entryTypes: ['measure'] });
 
 setTimeout(() => {}, 1000);
 ```
@@ -1884,7 +1884,7 @@ const obs = new PerformanceObserver((list) => {
   performance.clearMeasures();
   obs.disconnect();
 });
-obs.observe({ entryTypes: ['function'], buffered: true });
+obs.observe({ entryTypes: ['function'] });
 
 require('some-module');
 ```