GlobalVersions.md: wrong GETORIGINALFWDFEE formula

[pyAndr3w]

GlobalVersions.md states that GETORIGINALFWDFEE returns fwd_fee * 2^16 / first_frac, but the actual opcode in crypto/vm/tonops.cpp computes fwd_fee * 2^16 / (2^16 - first_frac)

Please update the changelog so the documented formula matches the real calculation.

ton/doc/GlobalVersions.md

Line 85 in 5c03491

* `GETORIGINALFWDFEE` (`fwd_fee is_mc - orig_fwd_fee`) - calculate `fwd_fee * 2^16 / first_frac`. Can be used to get the original `fwd_fee` of the message.

ton/crypto/vm/tonops.cpp

Line 360 in 5c03491

stack.push_int(td::muldiv(fwd_fee, td::make_refint(1 << 16), td::make_refint((1 << 16) - prices.first_frac)));