Some features need UX hints if user settings interfere

[julianlam]

There are a couple of features in NodeBB that can be affected by user settings, and it may look like they don't work based on setting.

A couple examples

• notificationType_new-topic-with-tag, When a topic is posted with a tag you follow
• notificationType_new-reply, When a new reply is posted in a topic you are watching

If either of those settings is set to "None", then notifications won't be sent. This is by design, but leads to situations where if you are no longer aware of your setting, then it seems like it does not work.

A toaster hint would be welcome if watching a tag or explicitly setting topic watch state, respectively.