At the moment, all topic `?page=` views are served with exactly identical page titles. If you search for something which is mentioned many times in the same Discourse topic, this makes for some very hard-to-understand search results! All the result titles are exactly the same, with no indication of why there are multiple results showing.
This commit adds a `- Page #` suffix to the titles in this situation. This lines up with our existing strategy for topic-list pagination.