Handle CategoryViewer hooks for prettier output

Depends on core patch introducing hooks. Changes the output
of flow topics within the category pages from:

<a href="...">Topic:S09u3r09ujf</a>

to

<a href="...">Hello can you help me</a> on <a href="...">Talk:Help</a>

Bug: T87793
Related-core-patch: I182e6e35fcc3a2a298e928e088579bdb22e145ff
Change-Id: Ia4f2953bcd807ba3990e762a2efcaab428c40147