~jaro/balkon

ref: e9a66c263f577e003e031e881e3b8bf1e7938ea0 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.