public static String format(TokenTree root) {
        return format(root, 120);
    }
Formats the given token tree, wrapping lines at 120 characters.

@param root Root {@link TreeType#IDL} tree node to format.
@return Returns the formatted model as a string.
@throws ModelSyntaxException if the model contains errors.
smithy-syntax/src/main/java/software/amazon/smithy/syntax/Formatter.java