As a user
When I go to https://meta.wikimedia.beta.wmflabs.org/w/api.php?action=help&modules=discussiontoolssubscribe
And I read the documentation of the "commentname" parameter

Actual result:
"Name of the comment to reply to. Only used when paction is addcomment. This parameter is required."

Expected result:
"paction" is not a part of this api module, its from action=discussiontoolsedit. It shouldn't be mentioned here. This api module doesn't add replies, its for topic subscriptions. The issue comes from trying to reuse the same documentation message (apihelp-discussiontoolsedit-param-commentname) from the other api module, instead of adding a new message that actually explains how the parameter is used in this module.