Correct Nob_Cmd_Opt documentation

[jnsh-rf]

source:

NOBDEF bool nob_cmd_run_opt(Nob_Cmd *cmd, Nob_Cmd_Opt opt)
{
    bool result = true;
    Nob_Fd fdin  = NOB_INVALID_FD;
    Nob_Fd fdout = NOB_INVALID_FD;
    Nob_Fd fderr = NOB_INVALID_FD;
    Nob_Fd *opt_fdin  = NULL;
    Nob_Fd *opt_fdout = NULL;
    Nob_Fd *opt_fderr = NULL;
    Nob_Proc proc = NOB_INVALID_PROC;

    size_t max_procs = opt.max_procs > 0 ? opt.max_procs : (size_t) nob_nprocs() + 1; // line 1325

	// (...) rest of the code
}