Display (single) line breaks properly in markdown comments

Summary

When commenting and adding a line break it does not get rendered.

I don't know whether it is supposed to render Markdown like that, but at least I am used from GitHub that also single line breaks (without an empty line in between) gets rendered as a line break.

Steps to reproduce

Enter some text into comment box or description of an issue, press enter (only one time) and write some more text.