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.

Add paragraph pagination.

Implement splitting ParagraphLayout into lines.

Implement generic pagination internally.

Separate module for the ParagraphLayout type.

Remove collapsible spaces at beginning of lines.

Allow empty lines when hard line breaking.

Support hard line breaks.

Add internal functions for "shaped runs" output.

Document considerations for beginsText/endsText.

Properly use ICU locale identifiers.