Refactor open_new_blocks

[digitalmoksha]

An attempt to refactor open_new_blocks a little, to help in reading the code.

@kivikakk let me know if you're ok with something like this. I wouldn't think it would affect performance too much. Let's see if our built-in benchmark has numbers.

[github-actions]

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
./bench.sh ./comrak-cd8d884	313.1 ± 1.2	311.9	318.4	2.87 ± 0.02
./bench.sh ./comrak-main	314.5 ± 5.8	311.1	341.7	2.88 ± 0.06
./bench.sh ./pulldown-cmark	109.2 ± 0.8	108.0	111.0	1.00
./bench.sh ./cmark-gfm	117.2 ± 0.6	116.5	118.3	1.07 ± 0.01
./bench.sh ./markdown-it	468.9 ± 0.8	467.6	471.1	4.29 ± 0.03

Run on Thu Dec 12 21:57:54 UTC 2024

[digitalmoksha]

/run-bench

[kivikakk]

Yep, happy to clean this up :)