Fix Cross-refs

Relinks xrefs to the proper targets once the chapter FM files are broken into topics in the current file or book.

This command relies on proper setup of various parameters in the fm2dita.ini file. In particular the following parameters must be set up as needed:

Important: Do not change the value of these INI parameters after running this command. Changes will result in misnamed files when using the Write XML Topics command as well as the map building commands.

It is also important to set the chapter numbering in the book file if the file naming is based on chapter numbering.

This command must be run after the EDD has been applied and the Assign IDs to Topics command has been run.