Although this improves the style, an ulterior motive is to keep the two
table links from breaking across lines in PDF output, per complaint from
Josh Kupershmidt.
Block elements with verbatim formatting (literallayout, programlisting,
screen, synopsis) should be aligned at column 0 independent of the surrounding
SGML, because whitespace is significant, and indenting them creates erratic
whitespace in the output. The CSS stylesheets already take care of indenting
the output.
Assorted markup improvements to go along with it.