No formatting on multi-line tag messages

Currently commit messages are shown in a <pre> tag to preserve the formatting of the message. This is not true for tag messages however, they are just shown as text in a <h4> element (or in a <div> in the non-released 'master').

I usually include a changelog but after recently migrating to GitLab I notices that the tag view is not almost useless for me as it is just a blob of non-formatted characters.

How things look: