Empty line prevents HTML comments from ending

[ryangalamb]

The following snippet (outside a code block) prevents the comment from ending.

<!--

-->

It looks like any multi-line comment with an empty line triggers the bug. The following snippet ends the comment successfully:

<!--

<!-- -->

Here's a demonstration of the bug in the live editor: bug repro link

(Follow the link, exit reading mode and then click in the editor section to make the raw markdown appear.)