Broken link warnings are too prominent

[AlexDaniel]

After 90d7ce4 broken link warnings are too prominent:

That's not something we should throw into the face of our users.

In fact, it is probably better to not wait for our users to complain, but to crawl the website and check for 404's yourself. That's what checklink does, see #561. Some time ago the output was a bit too verbose, but now that special characters are escaped the output is much more digestable.

[AlexDaniel]

I think that it is fixed now.