Pull content into topics (topicpull)
The topicpull step pulls content into <xref> and
<link> elements. This step is implemented in XSLT.
If an <xref> element does not contain link text, the target is examined and the link
text is pulled. For example, a reference to a topic pulls the title of the topic; a reference to a list item
pulls the number of the item. If the <xref> element references a topic that has a short
description, and the <xref> element does not already contain a child
<desc> element, a <desc> element is created that contains the
text from the topic short description.
The process is similar for <link> elements. If the <link> element
does not have a child <linktext> element, one is created with the appropriate link text.
Similarly, if the <link> element does not have a child <desc>
element, and the short description of the target can be determined, a <desc> element is
created that contains the text from the topic short description.