Issue link renderer is too eager and will try to render color hashes (BB-3038)

I pasted a small clip of CSS into an issue tracker comment, inside a block level {{{}}} code block. It displays a hex colour code like so: {{

{# 99ab50}

}} (no space) appears as {{

{<<issue 99>>ab50}

}}, even though it is inside a no-format block.

On editing the comment, I discovered that it is still stored as I typed it, therefore the conversion to {{

{<<issue 99>>}

}} must happen on rendering.

EDIT: it obviously happens on inline no-format blocks as well (but doesn't occur in the preview box before posting).