rubygems/guides — pull request #82 by lemuelf (2014-04-24 10:07:36+00:00)
Title: Change fragment name word separators to hyphens.

Not sure what changed (something in Markdown, maybe) but fragment names (ids) generated from headings are now being word-separated with hyphens and no longer with underscores, which broke the links. This change makes the links work again.