RFC: change the rules for default --forecast period ?

[Simon Michael]

Hi all,

at https://github.com/simonmichael/hledger/issues/1648 and friends we are trying to improve the rules deciding the the start and end of --forecast's transaction-generating period. We'd like to make them simpler, easier to understand and remember, and intuitive-behaving in more situations. 

Changes that help one situation might hurt another that we have not considered. So if you can take a look at this issue and share any input based on your own --forecast usage and needs, it will be quite helpful !