PaymentChannelFund

The only substantive change to this topic is to replace "XRP" with "XRP or fungible tokens" and the definition of an Amount as an Object or String.

For the full draft topic in context, see https://xrpl-dev-portal--token-payment-channels-and-escrows.preview.redocly.app/docs/references/protocol/transactions/types/paymentchannelfund.