Special characters in ``` blocks are replaced with HTML escape codes, and links within are received as markdown but not parsed

[thomas-profitt]

The corresponding Slack message appears as:

Example: -> example.com -> example.com

[thomas-profitt]

Slack may be sending us markdown in code blocks when there are links in code blocks (ugh), in which case we should strip it down to the literal text (in this case, "example.com") to match what's seen in Slack (Riot, for one, will recognize links in code blocks and display them as links, as in the screenshot above, so the functionality is still there)