The dm_topics "not a forum" warning and the matching docs section told
users to tap the bot's name in the DM and toggle "Topics" in chat
settings. That toggle only exists for group forums; a bot DM has no
such control. The actual prerequisite is Threaded Mode, enabled by the
bot owner via the BotFather Mini App (Bot Settings -> Threads
Settings) -- already documented correctly a few sections later in the
same file, under the /topic prerequisites.
Fixes#115019
0c872b611c