move options into their own module.

[kivikakk]

No description provided.

[github-actions]

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
./bench.sh ./comrak-c0b2574	105.3 ± 1.2	103.6	108.6	1.83 ± 0.03
./bench.sh ./comrak-main	105.7 ± 1.1	103.8	107.9	1.83 ± 0.03
./bench.sh ./pulldown-cmark	57.6 ± 0.9	56.7	60.2	1.00
./bench.sh ./cmark-gfm	88.1 ± 8.9	79.4	104.9	1.53 ± 0.16
./bench.sh ./markdown-it	253.1 ± 2.3	248.9	257.4	4.39 ± 0.08

Run on Mon Oct 20 07:35:47 UTC 2025