improvements from #617.

[kivikakk]

Also test benchmark post-#624.

[github-actions]

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
./bench.sh ./comrak-d983fea	147.8 ± 1.4	145.4	152.6	2.51 ± 0.05
./bench.sh ./comrak-main	148.4 ± 1.5	146.7	154.6	2.52 ± 0.05
./bench.sh ./pulldown-cmark	58.8 ± 1.0	57.6	62.3	1.00
./bench.sh ./cmark-gfm	87.7 ± 7.3	81.2	106.6	1.49 ± 0.13
./bench.sh ./markdown-it	403.5 ± 4.9	394.4	415.0	6.86 ± 0.15

Run on Sat Oct 18 05:22:29 UTC 2025

[kivikakk]

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
./bench.sh ./comrak-0f9ade6	150.8 ± 1.0	149.3	153.4	2.53 ± 0.05
./bench.sh ./comrak-main	150.3 ± 0.9	148.4	152.1	2.53 ± 0.05
./bench.sh ./pulldown-cmark	59.5 ± 1.0	58.5	62.5	1.00
./bench.sh ./cmark-gfm	87.5 ± 7.6	81.5	108.8	1.47 ± 0.13
./bench.sh ./markdown-it	406.5 ± 3.4	398.2	413.2	6.83 ± 0.13

Run on Sat Oct 18 05:05:00 UTC 2025

Yay! For comparison, the last run:

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
./bench.sh ./comrak-42547f2	307.6 ± 1.7	306.3	313.0	2.91 ± 0.03
./bench.sh ./comrak-main	311.1 ± 2.6	308.3	321.4	2.94 ± 0.03
./bench.sh ./pulldown-cmark	105.7 ± 0.8	104.4	107.6	1.00
./bench.sh ./cmark-gfm	116.1 ± 1.3	113.7	118.4	1.10 ± 0.02
./bench.sh ./markdown-it	471.7 ± 2.0	468.8	479.1	4.46 ± 0.04

Run on Thu Oct 16 00:35:24 UTC 2025

Removing Minimising process creation overhead has brought all times lower, and removing syntax highlighting from Comrak has brought its times down significantly. markdown-it does appear to be doing syntax highlighting too; will address that. I'm surprised to see its time increase; like it's not handling larger documents as well as smaller ones.

[kivikakk]

/run-bench