~jaro/balkon

ref: a42dd23609b364bf2e4375d8205c1623e4155522 balkon/src d---------
Integrate BiDi reordering.
Implement BiDi resolved level reordering.
Represent lines with non-empty lists.

We can do this because we removed lines with zero size.
Remove lines with zero size.

These lines would otherwise affect line numbering.
Do not re-export through the Plain module.
Move paragraphSpanBounds to the correct module.
Clarify comment about BiDi.
Correct comment about fragmentation.
Fix style: long lines.
Fix style: small Prelude imports.
Fix style: external vs internal imports.
Fix style: white space in lambdas.
Fix style: white space around operators.
Fix style: white space in exports and imports.
Fix style: bullet points in comments.
Fix style: non-ASCII characters in comments.
Mark some lists as explicitly non-empty.
Fix typos in comments.
Improve documentation for pagination.
Prepare pagination for future layout types.
Next