docs(declarations): correct grammar

subjects/declarations/README.md

@@ -4,22 +4,25 @@
 
 Create the following constant variables:
 
-- `escapeStr`, that contains the following specials characters: `` ` ``, `\`, `/`, `"`, `'`
+- `escapeStr`: a `string` which contains the following special characters: `` ` ``, `\`, `/`, `"` and `'`.
-- `arr` that is an array containing the values 4 and '2'
+- `arr`: an array containing the values `4` and `'2'`.
-- `obj` that is an object containing a property for each primitives:
+- `obj`: an object containing primitive values:
-  - `str` for `String`
+  - `str`: with a `string` value.
-  - `num` for `Number`
+  - `num`: with a `number` value.
-  - `bool` for `Boolean`
+  - `bool`: with a `boolean` value.
-  - `undef` for `undefined`
+  - `undef`: with a `undefined` value.
-- A `nested` object that contains
+- `nested`: an object containing:
-  - arr: an array of the 3 values: 4, undefined, '2'
+  - `arr`: an array of 3 values: `4`, `undefined` and `'2'`.
-  - obj: an object with 3 property (str, num & bool)
+  - `obj`: an object with 3 properties
+    - `str` with a `string` value.
+    - `num` with a `number` value.
+    - `bool` with a `boolean` value.
 
-`nested`, `arr` and `obj` must be frozen to prevent changes from them.
+`nested`, `arr` and `obj` must be frozen, so that their elements or properties cannot be changed.
 
 ### Notions
 
 - Primitive and Operators
 - Variables
-- [nan-academy.github.io/js-training/examples/data-structures.js](https://nan-academy.github.io/js-training/examples/data-structures.js)
+- [Data Structures](https://nan-academy.github.io/js-training/examples/data-structures.js)
-- [devdocs.io/javascript/global_objects/object/freeze](https://devdocs.io/javascript/global_objects/object/freeze)
+- [Freeze](https://devdocs.io/javascript/global_objects/object/freeze)