Add -jobs option

[hhatto]

What's this?

enabled the -jobs option for performance enhancement when using the -w or -l option.

When a number greater than or equal to 2 is assigned to the -jobs option, an equivalent number of goroutine workers are launched.
These workers handle code formatting tasks, thereby parallelizing the process and enhancing performance as a result.

The results below demonstrate my use case both without the -jobs option and with the -jobs option set to 4.
I executed each of the -w or -l options three times in both scenarios.
There was approximately a 30% performance increase.

Cases without specifying -jobs option:

$ time golines -l ./
golines -l ./  72.06s user 252.78s system 1035% cpu 31.360 total
golines -l ./  68.15s user 232.71s system 1015% cpu 29.613 total
golines -l ./  71.16s user 251.04s system 1041% cpu 30.926 total

$ time golines -w ./
golines -w ./  64.21s user 227.85s system 1045% cpu 27.946 total
golines -w ./  65.72s user 221.50s system 965% cpu 29.762 total
golines -w ./  66.27s user 228.43s system 997% cpu 29.554 total

Cases with the -jobs option set to 4:

$ time ./golines.jobs -j 4 -l ./
./golines.jobs -j 4 -l ./  68.51s user 201.23s system 1403% cpu 19.219 total
./golines.jobs -j 4 -l ./  70.68s user 208.27s system 1380% cpu 20.204 total
./golines.jobs -j 4 -l ./  67.81s user 198.54s system 1406% cpu 18.942 total

$ time ./golines.jobs -j 4 -w ./
./golines.jobs -j 4 -w ./  70.34s user 207.37s system 1400% cpu 19.836 total
./golines.jobs -j 4 -w ./  72.11s user 212.88s system 1410% cpu 20.211 total
./golines.jobs -j 4 -w ./  70.00s user 205.18s system 1364% cpu 20.168 total