Currently the category Wiki does not allow replies but does direct such to the category Wiki Discussion.
For the topic Announce there really should be no replies. If a question or such is needed, then a new topic should be created with a link and/or tag to the announced item.
If applied the current replies would be moved into new topics so as not to lose them.
EDIT
The conversion of the categories Announce and Useful Code is done. All topics now have 0 replies. For any topic with a reply the replies were moved to a new topic. While Discourse will not allow me to configure it so that there is no reply button, any reply in the Announce or Useful Code category should now be trapped by the system and placed in the moderator queue for action.
What if the poster wants to make some update or comment while keeping the original post? Would there be a link in the original post to the moved reply? I also surmise it would clutter the forum to start a new topic for every reply; but perhaps I am misunderstanding what no reply means.
Everyone who has an account here should be able to edit their own post. If they don’t have an account and are logging in anonymously then they should get an account.
There should be no replies in these categories. The poster should start a new topic and add a reference to the topic they are referencing.
The limiting of replies only applies to a very few categories. The problem with replies in these categories is that they tend to start several different topics related to the original topic but are actually independent topics from the replies. So it is just easier to keep all of the replies for these categories separate from the start.
Once a new topic is started in a different category, other can reply as normal.
If Discourse allowed the topic and replies to be displayed as a tree, then there would not be a need to impose this restriction. I don’t expect Discourse to change and don’t plan on asking them either.
It means that there should be no replies in the category. If you look at a category with no replies allowed, e.g. Announce, it will have no replies.
As there is no way at present to enforce this other than trapping replies and manually adjusting, sometimes replies will be posted, but then they will be moved.