FmtStr does not take numbwritten bytes into account

[yvgny]

When executing the method execute_writes(), the numbwritten argument is not taken into account, so the written values are wrong.

Location in code:

pwntools/pwnlib/fmtstr.py

Line 901 in 91d464b

fmtstr += fmtstr_payload(self.offset, self.writes, numbwritten=self.padlen, write_size='byte')

As suggested in #1139, a solution would be to add numbwritten to padlen so that both of the values are taken into account, but it seems that the issue was never solved.