Update MyString.java

[123himanshi-khatri]

This pull request contains the submission for Task 1 of the Java String Operations assignment.
Features implemented in the MyString class:

1. append(String newString)

   • Appends a string to the current string with proper spacing.

2. countWords()

   • Counts the number of words in the current string.

3. replace(String a, String b)

   • Replaces all occurrences of a substring with a new string with descriptive prompts.

4. isPalindrome()

   • Checks if the current string is a palindrome (ignores spaces and case).

5. splice(int start, int length)

   • Removes a substring starting at a given index with a given length.

6. split(String pattern)

   • Splits the string using a user-defined pattern and displays the parts.

7. maxRepeat()

   • Finds and displays the character that repeats the most in the string.

8. sort()

   • Sorts all characters in the string alphabetically.

9. shift(int n)

   • Shifts the first n characters to the end of the string.

10. reverse()

    • Reverses the current string.
      All changes are committed to the branch Assignment_Task1 and are ready for review.