Update sha256 estimates

src/sha256.ts

@@ -2,7 +2,7 @@ import { HashMD, Chi, Maj } from './_md.js';
 import { rotr, wrapConstructor } from './utils.js';
 
 // SHA2-256 need to try 2^128 hashes to execute birthday attack.
-// BTC network is doing 2^67 hashes/sec as per early 2023.
+// BTC network is doing 2^70 hashes/sec (2^95 hashes/year) as per late 2024.
 
 // Round constants:
 // first 32 bits of the fractional parts of the cube roots of the first 64 primes 2..311)