Replace .ti operations with equivalent .RS/.RE pairs.

This change makes automatic lifting to XML-DocBook possible, and
should enable generation of better-quality HTML from these pages.
Replace .IP o with .IP \(bu, using the [nt]roff bullet character.

This will improve the quality of generated HTML. There is a cost,
which is that most terminal emulators will just display the bullet
as a (less visible) dot.  An alternative to this change would be
to use a * character for the bullet.
Remove another .ti for .RS/.RE, and remove a .TP that broke list parsing.
Re-layout a FILES section in the traditional style.
Restore use of correct alternation syntax using { | }.

This is required in order for ther synopsis to be translated into the
corresponding XML markup.
Fix broken list syntax.

Bodiless .TP entries and unterminated .TP lists interfere with page
parsing.