doc: fix uncaught exception example

PR-URL: nodejs#51638
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Akhil Marsonya <akhil.marsonya27@gmail.com>

doc/api/process.md

@@ -360,12 +360,13 @@ exit with 0.
 
 ```mjs
 import process from 'node:process';
+import fs from 'node:fs';
 
 process.on('uncaughtException', (err, origin) => {
   fs.writeSync(
     process.stderr.fd,
     `Caught exception: ${err}\n` +
-    `Exception origin: ${origin}`,
+    `Exception origin: ${origin}\n`,
   );
 });
 
@@ -380,12 +381,13 @@ console.log('This will not run.');
 
 ```cjs
 const process = require('node:process');
+const fs = require('node:fs');
 
 process.on('uncaughtException', (err, origin) => {
   fs.writeSync(
     process.stderr.fd,
     `Caught exception: ${err}\n` +
-    `Exception origin: ${origin}`,
+    `Exception origin: ${origin}\n`,
   );
 });