r1.83 of doc/handbook/handbook.sgml

as to authors.ent, and add an ENTITY line to handbook.sgml.

freebsd.dtd.

these changes;

 1. Remove '<tt>' and '</tt>'.

 2. Search/replace

      \s-+<htmlurl url='mailto:\([^']+\)'\s-+name='[^']+'>

    with

       <email>\1</email>

    (there's a leading space before <email>)

Added an ENTITY line to handbook.sgml to use the new entities.

<!--
     Local Variables:
     mode: sgml
     sgml-indent-data: t
     sgml-omittag: nil
     sgml-shorttag: nil
     sgml-always-quote-attributes: t
     sgml-minimize-attributes: max
     End:
-->

to handbook.sgml

Added

<!--
     Local Variables:
     mode: sgml
     sgml-declaration: "../chapter.decl"
     sgml-indent-data: t
     sgml-omittag: nil
     sgml-shorttag: nil
     sgml-always-quote-attributes: t
     sgml-minimize-attributes: max
     sgml-parent-document: ("../handbook.sgml" "part" "chapter")
     End:
-->

to the bottom of each chapter.sgml file so that Emacs can do the right
thing.

chapter.sgml in a directory named according to the value the id
attribute on that chapter.

Added chapters.ent, which lists the entities for each chapter.

Updated handbook.sgml to use these entities.