improve description of the defineProperty() method (mdn#20002)

* improve description of the defineProperty() method

values added using Object.defineProperty() is not by default immutable, it depends on the value itself.

* improve description of the defineProperty() method

values added using Object.defineProperty() is not by default immutable, it depends on the value itself.

* make defineProperty method's description more comprehensive

* Update index.md

Co-authored-by: Joshua Chen <sidachen2003@gmail.com>

Author: Ahmed-Hakeem

files/en-us/web/javascript/reference/global_objects/object/defineproperty/index.md

@@ -43,8 +43,8 @@ Normal property addition through assignment creates properties which show up dur
 property enumeration ({{jsxref("Statements/for...in", "for...in")}} loop or
 {{jsxref("Object.keys")}} method), whose values may be changed, and which may be
 {{jsxref("Operators/delete", "deleted", "", 1)}}. This method allows these extra details
-to be changed from their defaults. By default, values added using
-`Object.defineProperty()` are immutable and not enumerable.
+to be changed from their defaults. By default, properties added using
+`Object.defineProperty()` are not writable, not enumerable, and not configurable.
 
 Property descriptors present in objects come in two main flavors: data descriptors and
 accessor descriptors. A **data descriptor** is a property that has a