Solve message splitting and board crushing

##### Question LeetCode 2468. Split Message Based on Limit – Given a message string and a per-line width, split it into parts adding the suffix "<i/n>" (e.g., 1/8, 2/ 8). Follow-up: perform the split when the suffix length itself must be counted within the width. LeetCode 723. Candy Crush – Given an m × n board, repeatedly crush all rows or columns containing ≥3 identical adjacent candies, apply gravity, and return the board when it reaches a stable state. https://leetcode.com/problems/split-message-based-on-limit/description/ https://leetcode.com/problems/candy-crush/description/