adding text to Thunder Bolt Spell

WeaponsList["thunder bolt"] = {
    regExpSearch: /^(?=.*thunder)(?=.*bolt).*$/i,
    name: "Thunder Bolt",
    source: ["Nythoria", 2],
    list: "spell",
    ability: 6, // Charisma
    type: "Cantrip",
    damage: ["C\xD7" + 1, 10, "thunder"],
    range: "60 ft",
    description: "Each d10 is a separate bolt requiring separate rolls",
    abilitytodamage: false
};

calcChanges: {
        atkAdd: [
            function (fields, v) {
                if (v.baseWeaponName === "thunder bolt" && /thadlor's crescendo - exalted/i.test(v.WeaponTextName)) {
                    fields.Description += (fields.Description ? '; ' : '') + '+2d6 lightning damage';
                    fields.Damage_Die[1] += 12; // Add 2d6 lightning damage
                }
            },
            "Thadlor's Crescendo - Exalted allows the bard to cast Thunder Bolt at will, dealing an additional 2d6 lightning damage."
        ]
    },