Backslash escaping removes new line

[Destroyer]

The following doesn't work as expected

hello
\- world

when tested on https://spec.commonmark.org/dingus/ it shows the result on one line, ommiting line break.

As element uses commonmark it has the same issue.

[jgm]

This has nothing to do with backslash escaping.
By default, line breaks are treated like spaces, so you can hard-wrap text.
If you want them treated as hard breaks instead, the README.md explains how to do that:

For example, to make soft breaks render as hard breaks in HTML:

var writer = new commonmark.HtmlRenderer({softbreak: "<br />"});