fix: correct spelling errors in SubsequenceRecursive.js and AlphaNumericPalindrome.js

Author: mbatwc113114

String/AlphaNumericPalindrome.js

@@ -1,31 +1,33 @@
 /**
  * @function alphaNumericPalindrome
- * @description alphaNumericPalindrome should return true if the string has alphanumeric characters that are palindrome irrespective of special characters and the letter case.
+ * @description alphaNumericPalindrome should return true if the string has alphanumeric characters that form a palindrome,
+ * regardless of special characters and letter case.
  * @param {string} str the string to check
  * @returns {boolean}
  * @see [Palindrome](https://en.wikipedia.org/wiki/Palindrome)
  * @example
  * The function alphaNumericPalindrome() receives a string with varying formats
- * like "racecar", "RaceCar", and "race CAR"
+ * like "racecar", "RaceCar", and "race CAR".
  * The string can also have special characters
- * like "2A3*3a2", "2A3 3a2", and "2_A3*3#A2"
+ * like "2A3*3a2", "2A3 3a2", and "2_A3*3#A2".
  *
  * But the catch is, we have to check only if the alphanumeric characters
- * are palindrome i.e remove spaces, symbols, punctuations etc
- * and the case of the characters doesn't matter
+ * form a palindrome, i.e., remove spaces, symbols, punctuation, etc.
+ * The case of the characters doesn't matter.
  */
 const alphaNumericPalindrome = (str) => {
   if (typeof str !== 'string') {
     throw new TypeError('Argument should be string')
   }
 
-  // removing all the special characters and turning everything to lowercase
+  // Remove all non-alphanumeric characters and convert to lowercase
   const newStr = str.replace(/[^a-z0-9]+/gi, '').toLowerCase()
+
   const midIndex = newStr.length >> 1 // x >> y = floor(x / 2^y)
 
   for (let i = 0; i < midIndex; i++) {
     if (newStr.at(i) !== newStr.at(~i)) {
-      // ~n = -(n + 1)
+      // ~n = -(n + 1), used to get characters from the end
       return false
     }
   }