doc: add a example code to API doc property

example code added to the process.setgroups() API
doc property in process.md

PR-URL: #35738
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

doc/api/process.md

@@ -2210,7 +2210,18 @@ The `process.setgroups()` method sets the supplementary group IDs for the
 Node.js process. This is a privileged operation that requires the Node.js
 process to have `root` or the `CAP_SETGID` capability.
 
-The `groups` array can contain numeric group IDs, group names or both.
+The `groups` array can contain numeric group IDs, group names, or both.
+
+```js
+if (process.getgroups && process.setgroups) {
+  try {
+    process.setgroups([501]);
+    console.log(process.getgroups()); // new groups
+  } catch (err) {
+    console.log(`Failed to set groups: ${err}`);
+  }
+}
+```
 
 This function is only available on POSIX platforms (i.e. not Windows or
 Android).