clarify the two Cadence precompiles use cases: revertible and commit-reveal
clarify prevrandao current security
FVM:
move sections about FLIP123 and FLIP120 that were put in the wrong context
remove confusing mentions of PRGs and random streams/sequences from the main sections. These are all details that confuse the doc and dilute the main idea: use a revertible randomness or use a commit-reveal scheme.
EVM:
FVM: