doc: fix small typo in process.md

PR-URL: #57333
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: Felix Rieseberg

doc/api/process.md

@@ -4218,7 +4218,7 @@ added: REPLACEME
 -->
 
 * `previousValue` {Object} A previous return value from calling
-  `process.cpuUsage()`
+  `process.threadCpuUsage()`
 * Returns: {Object}
   * `user` {integer}
   * `system` {integer}