[Nit] Payment transaction docs: IssuedCurrencies in lower case

[ckeshava]

The documentation asks that Issued Currencies be specified in lower-case in the Amount, DeliverMax and the DeliverMin fields.

For non-XRP amounts, the nested field names are lower-case.

This does not appear to be true in practice. The responses of tx command pertaining to Payment transactions return upper-case Issued Currency representations: https://xrpl.org/resources/dev-tools/websocket-api-tool?server=wss%3A%2F%2Fxrplcluster.com%2F&req=%7B%22id%22%3A%22example_Payment%22%2C%22command%22%3A%22tx%22%2C%22transaction%22%3A%227BF105CFE4EFE78ADB63FE4E03A851440551FE189FD4B51CAAD9279C9F534F0E%22%2C%22binary%22%3Afalse%7D

I suspect we can submit upper-case IssuedCurrency representations in Payment transaction inputs too (I haven't been able to check it yet). Is the above statement true today?