doc: fix comment in assert.md

PR-URL: nodejs/node#16335
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>

doc/api/assert.md

@@ -441,7 +441,7 @@ assert.notDeepEqual(obj1, obj3);
 // AssertionError: { a: { b: 1 } } notDeepEqual { a: { b: 1 } }
 
 assert.notDeepEqual(obj1, obj4);
-// OK, obj1 and obj2 are not deeply equal
+// OK, obj1 and obj4 are not deeply equal
 ```
 
 If the values are deeply equal, an `AssertionError` is thrown with a `message`