~jaro/balkon

ref: cebfb4e28e07f2707240abe1f4fe3cd4aeff2cc5 balkon/src/Data/Text/ParagraphLayout/Internal/WithSpan.hs -rw-r--r-- 1.2 KiB 
Allow extracting ResolvedBox from WithSpan.

Separate WithSpan for sharing with other modules.