constructor(isLeaf, children) {
        this.isLeaf = isLeaf;
        this.children = children;
    }
Create a new CharTrieNode.
@param {boolean} isLeaf Whether the node is a leaf node or not.
@param {Map<string, CharTrieNode>} children A map containing the node's children, where the key is a character and the value is a `CharTrieNode`.