doc: fix property name 'detail' of performanceEntry

Hello,

I noticed that the performanceEntry that is passed to the callback of PerformanceObserver does not have a property details but it does have a property detail (without the "s"). This is also in line with the deprecation warning and what I could find in the source code:

https://github.com/nodejs/node/blob/1c4df352b77514e93a46fb27e996755d45a0b530/lib/internal/perf/performance_entry.js#L44 https://github.com/nodejs/node/blob/1c4df352b77514e93a46fb27e996755d45a0b530/lib/internal/perf/performance_entry.js#L63 https://github.com/nodejs/node/blob/1c4df352b77514e93a46fb27e996755d45a0b530/lib/internal/perf/observe.js#L75

In case this is correct: I have changed the documentation accordingly. Please let me know if I can do anything else.

Thank you!