- adding markup

- reformatting a bit
- <em> -> <var>
- add seealso to UseCanonicalName
- add explicit XHTML example
- " inside quoted text is not impossible, it can be written as &quot;


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@97520 13f79535-47bb-0310-9956-ffa450edef68