git effort bad substitution error

Hello,



```bash
/opt/homebrew/bin/git-effort: line 272:  ${nJobs@P} >= nProcs : bad substitution
```

related code:

```bash
# send paths to effort
nPaths=${#paths[@]}
nProcs=$(procs)
nJobs="\j"
for ((i=0; i<nPaths; ++i))
do
    while (( ${nJobs@P} >= nProcs )); do
        wait -n
    done
    effort "${paths[i]}" &
done|tee $tmp
```

What does `nJobs="\j"` mean?