c745c97e5f add input weight predictions for p2pkh outputs (conduition)
Pull request description:
Adds input weight prediction constant and `ground_p2pkh_*` methods, mirroring those for `P2WPKH`. This seemed to be missing.
ACKs for top commit:
tcharding:
ACK c745c97e5f
apoelstra:
ACK c745c97e5f
Tree-SHA512: 69b4484686ecf761b766d2a7d7408c784981a9ba8c4aa8abd9d8655bd9421eb882e346ece232530edf9edff602d2fe1570992a5eb7b420b928d8b13397d2f60f