Wrap lines, whitespace cleanup and add some missing "</para>".

Submitted by: Hiroki Kobayashi <solidsneak at hyper.cx>
Reviewed by: Hiroo Ono <hiroo _at_ jp dot FreeBSD dot org>

		Ryusuke Suzuki <ryusuke _at_ jp dot FreeBSD dot org>

References: [doc-jp-work 1503, 1524, 1529, 1599, 1799]