Issue link renderer is too eager and will try to render color hashes (outside of code blocks) (BB-8874)

in issue BCLOUD-3273 this bug was first reported, but only for hex color codes inside of code blocks.
but this is also an issue in normal issue content.

lets take for example the hex color # 3c9ec5 it would link this issue to issue 3 (see screenshot)

of course one could argue, "such color codes should be in a code block anyway".
but I think this issue is still worth having a look at (especially since at lest on my projects the issue tracker is used by non developers as well)