Factor out inlines::Scanner, and Other Such Cleanups.

[kivikakk]

No description provided.

[github-actions]

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
./bench.sh ./comrak-6db65fa	107.2 ± 1.2	105.6	110.0	1.81 ± 0.03
./bench.sh ./comrak-main	106.9 ± 1.2	105.0	109.6	1.81 ± 0.03
./bench.sh ./pulldown-cmark	59.1 ± 0.9	57.9	61.8	1.00
./bench.sh ./cmark-gfm	95.0 ± 4.7	84.6	103.4	1.61 ± 0.08
./bench.sh ./markdown-it	262.2 ± 2.6	257.4	267.5	4.43 ± 0.08

Run on Sat Nov 1 04:43:46 UTC 2025