[bug] Line length checking is not accurate

[Andrew15-5]

This is a sub-issue from #82 (see examples there). In https://github.com/astrale-sharp/typstfmt/commit/a9e6249019111783380be88390e86af3441076ab line length can exceed the configured line limit. Specifically, if the text (content block) is used, then it can be chopped into smaller lines which won't alter the output.

EDIT by @astrale-sharp The first line of a nested block also doesn't respect max_line_length (it's unaware of it's parent)