doc: mention constructor comparison in assert.deepStrictEqual

Updated `assert.deepStrictEqual` docs to explicitly mention that object constructors are included in the comparison.
This clarifies behavior consistent with `util.isDeepStrictEqual` and helps prevent confusion when comparing derived objects or proxy instances.

Author: hamzakargin

doc/api/assert.md

@@ -399,6 +399,8 @@ are also recursively evaluated by the following rules.
   both sides are {NaN}.
 * [Type tags][Object.prototype.toString()] of objects should be the same.
 * Only [enumerable "own" properties][] are considered.
+* Object constructors are also compared to ensure that instances are strictly deep-equal. 
+  This means that even if two objects share the same prototype and properties, differing constructors will result in inequality.
 * {Error} names, messages, causes, and errors are always compared,
   even if these are not enumerable properties.
 * [Object wrappers][] are compared both as objects and unwrapped values.