Search input: line breaks

[cengels]

The search currently does not support matches across multiple text blocks (i.e. paragraphs).

This seems to be an issue with Qt/QML first and foremost, as calling QTextDocment::find() with a regex containing \s, \u2029, \r or \n does not result in matches being found. It's quite possible that Qt/QML escapes the backslashes before passing them on to FormattableTextArea, which would explain why they're not working, but it's also possible there is another problem at work.

The TextHighlighter also currently does not support highlighting across multiple blocks, but that part at least is easy to implement. But before it can be implemented, QTextDocument::find() needs to return the right ranges.