When the doc/help subcollection is installed, the installer creates an
hdindex file.  See plt/collects/help/doc.txt for information about the
structure of such files.

To create index entries for Help Desk servlets, put anchor entries of
the form

  (a ([name "name"] [value "Index entry"]))

on a single line in the Scheme source.  The `name' attribute can be
any string that is unique among such anchors in that file, though of
course it should be mnemonic.  The `value' attribute is used as the
index entry that is matched against search strings in Help Desk, and
appears again as the link caption in the Help Desk search results.