Angle brackets within code blocks get removed

[sesse]

It seems there is some odd HTML stripping at work within code blocks (triple backticks). The simplest way to reproduce is to send a message to yourself containing

```<a>```

It comes out as

12:40:07 Sesse | ```
12:40:07       | a
12:40:07       | ```

This is rather cumbersome when trying to discuss the subtleties of HTML :-)

<a or a> comes out just fine, so I guess there's some stripping at work; the web client displays the tags verbatim. It also works just fine if I'm using double backticks only.

[trygveaa]

Ah, this is caused by the rendering changes I did a little while ago (commit 74da303, to fix #893 among others). I did a related fix in commit 6478c14, but apparently I only considered normal text and inline code there, not code blocks. It should be fixed now.