Update permitted `<title>` field format

[windymilla]

PG are updating their preferred <title> format to
<title>Alice's Adventures in Wonderland | Project Gutenberg</title>

pphtml's title check/message will need updating too.

[rtonsing]

It seems to be fine with it already - no warning or error, just a normal info either way:

[info] title/h1 compare:
title: The Murder of Roger Ackroyd | Project Gutenberg
h1: THE MURDER OF ROGER ACKROYD

Looks like it needs updating anyway, if there IS some issue, it needs to show the correct format in the warning.

[windymilla]

Fixed by #15