document: changes to fee calculation w.r. ref scripts

[ashisherc]

Please document if any changes coming to Conway era regarding fee calculation w.r.t ref scripts

[WhatisRT]

We have this line in the Conway spec: https://github.com/IntersectMBO/formal-ledger-specifications/blob/master/src/Ledger/Utxo.lagda#L132

I admit the notation is a bit confusing (this is for technical reasons - it used to have clearer notation). I don't know if we can reasonably improve that notation. Does that answer this issue?

[ashisherc]

The notation is good enough for me, but I am looking for a simpler explanation as well, also mentioning such a change that is coming with Conway. In the previous era specs, every change/new update being introduced are documented nicely.

[WhatisRT]

There should be a paragraph documenting this as part of the final spec.