BIP8: Make signalling during LOCKED_IN recommended rather than mandatory

[ajtowns]

With the addition of the MUST_SIGNAL phase, signalling during LOCKED_IN is no longer needed for activation coordination, so drop it.

[ajtowns]

At present, the only time anyone has to potentially immediately update their consensus rules is if the last block in a STARTED period pushes signalling over the threshold, at which point the next block has to immediately signal or is invalid. There's grace periods for everything else -- enforcing the rules has the 2016 blocks of LOCKED_IN between knowing it's coming and it actually happening; and the first block of MUST_SIGNAL (hopefully) has a few months of grace between everyone deciding to set lockinontimeout=true and timeoutheight actually arriving.

[jonasnick]

ACK
this seems to be a remnant from before MUST_SIGNAL and there's no reason to not have a grace period

[michaelfolkson]

ACK. LOCKED_IN is an end state on the happy path. Once we reach this state there are no requirements in terms of signaling. Continued signaling is a nice to have but has no impact on the path taken or the end result.

[benthecarman]

ACK this makes more sense

[achow101]

ACK 9a119ce

[ProofOfKeags]

ACK

[lucasmoten]

ACK

[AbelLykens]

ACK

[wangchun]

ACK

[AlejandroDeLaTorre]

ACK

[setpill]

ACK 9a119ce

[darosior]

ACK 9a119ce

[kaloudis]

ACK 9a119ce