~jaro/balkon

ref: 4ff2ea2a04080eb644de0fba63237633c025ab0d balkon/src/Data/Text/ParagraphLayout/Internal/Rich.hs -rw-r--r-- 3.1 KiB 
Link ResolvedSpan to boxes.

Separate WithSpan for sharing with other modules.

Add basic support for Rich layout.