fixes comment referring to other source code

source/common/arch/win/i386/base_dispatch.c was referring to:
see '/msf3/external/source/shellcode/x86/migrate/migrate.asm'
which was updated to:
see '/msf3/external/source/shellcode/windows/x86/src/migrate/migrate.asm'
and see '/msf3/external/source/shellcode/x64/migrate/migrate.asm'
was updated to:
see '/msf3/external/source/shellcode/windows/x64/src/migrate/migrate.asm'

## Verification

- [ ] not much, just edits a comment, I guess you can rebuild meterp if you desire

I wouldn't rebuild the binaries or update the gem since it's just a comment change