Bug #1235: Viewing a forum topic, "updated at" shows last reply date

Take pretty much any forum topic; example:

https://wincent.dev/forums/synergy/topics/242

Note how the first post of the topic will show a date info string like "Created 21 November 2008, edited yesterday".

That's because the first post was created on 21 November 2008, and the latest reply was "yesterday".

So while it is necessary to consider the "topic" as updated on that date (so that when viewing the list of topics in the forum it appears in appropriate last-updated order), it looks misleading on the actual topic show page because it makes it look like the original post was edited on that date.

Looks like I am going to need to change the view code only, suppressing the display of "edited at" info; I am happy with the way dates are actually stored at the model level. This seems the most sensible solution seeing as topic text actually being edited is a fairly rare occurrence.

In the longer term I am not sure if I need to actually have two "updated at" fields in topics; one showing when the topic as a whole was last replied to, and one showing when the topic text itself was actually edited.