Updated whitespace documentation

lib/node_modules/@stdlib/regexp/whitespace/README.md

@@ -111,6 +111,26 @@ var out = replace( str, reWhitespace.REGEXP_CAPTURE, '$1$1' );
 
 -   Matches one related white space character without the Unicode character property "WSpace=Y" (zero width non-breaking space which was deprecated as of Unicode 3.2).
 
+-   Unlike the \s shorthand in JavaScript, @stdlib/regexp/whitespace explicitly targets Unicode 9.0 white space characters, ensuring consistency and compatibility across environments. 
+    The predefined \s shorthand relies on the ECMAScript specification and may vary slightly in behavior, especially in older or less compliant environments.
+    Example demostrating difference
+    ```javascript
+    var testString = 'Hello\u200BWorld';
+
+    var regex = /\s/;
+    console.log(regex.test(testString)); // returns true in some engines(ES5 or older)
+
+    var reWhitespace = require( '@stdlib/regexp/whitespace' );
+    var RE_WHITESPACE = reWhitespace();
+    console.log(RE_WHITESPACE.test(testString)); // returns false
+
+    var arr = testString.split(regex);
+    console.log(arr);  // ["Hello", "World"]
+
+    arr = testString.split(RE_WHITESPACE);
+    console.log(arr);  // ["Hello\u200BWorld"]
+    ```
+
 -   The `REGEXP` regular expression is defined as 
 
     ```text