hg parents: don't pass an OS-specific path to repo.filectx
The only reason to use the matcher code instead of calling util.canonpath
directly is to be able to use "path:canonical/path/to/file" patterns.
<item>
<title>#desc|strip|firstline|strip|escape#</title>
<link>{urlbase}{url}rev/{node|short}</link>
<description><![CDATA[#desc|strip|escape|addbreaks#]]></description>
<author>#author|obfuscate#</author>
<pubDate>#date|rfc822date#</pubDate>
</item>