Introduce breaking changes to toString() method

[mohanvive]

Purpose

This PR introduces breaking changes to toString() method.
Please check, ballerina-platform/ballerina-spec#499 for more information.

[Update after #25753 https://github.com//pull/25753]
Please find a few examples below,

    xml argXML1 = xml `<TITLE>Empire Burlesque</TITLE>`;
    xml argXML2 = xml `<TITLE>Hide your heart</TITLE>`;
    any[] varArr = [argXML1, argXML2];

    varArr.toString() // [`<TITLE>Empire Burlesque</TITLE>`,`<TITLE>Hide your heart</TITLE>`]

    Address addr = {no: 24, country: "Sri Lanka", city: "Colombo", street: "Palm Grove"};
    addr.toString() // {"no":24,"country":"Sri Lanka","city":"Colombo","street":"Palm Grove"}

    xml argXML1 = xml `<TITLE>Empire Burlesque</TITLE>`;
    argXML1.toString() // <TITLE>Empire Burlesque</TITLE>

    public type FirstError distinct error;

    // normal error case
    error cause = error("Account not found", accountID = 123, name="Las", oop = ());
    cause.toString() // error("Account not found",accountID=123,name="Las",oop=null)

    // distinct error
    FirstError err = FirstError("Reason1", cause, detail = "Failed to get account balance");
    err.toString() // error FirstError ("Reason1",error("Account not found",accountID=123,name="Las",oop=null), detail="Failed to get account balance")