I can't find documentation about how to format text in Bugzilla. Does Bugzilla support Markdown, Textile or some sort of markup language out of the box?
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Half interesting news: there is an open P3 enhancement [1] for adding optional support for Markdown [2] and it is possible to voteup. Though it doesn't seem there is too much enthusiasm around it.
Edit: Bugzilla 6.0 will include optional markdown support; it was implemented as a GSoC project in the bug linked in the question. Docs.
Before 6.0, the only thing it supports is the > prefix on lines, which makes them purple and not wrap.