doc: translate from :hg:`help config.SECTION` to a valid link to hgrc.5.html Before this patch, ":hg:`help config.SECTION`" in online help text is translated to a link to "hg.1.html#config.SECTION" in HTML unintentionally. This patch translates from :hg:`help config.SECTION` in online help text to a valid link to "hgrc.5.html#SECTION" in HTML. This patch ignores element(s) under "SECTION" (e.g. "ITEM" of ":hg:`help config.SECTION.ITEM`"), because there is no way to refer directly to it in HTML, yet.