Clarify how @here works

Hi,

In every single Discord server I'm in, other users are mistaking "@here" for something like "ping those who want to be notified about the channel I'm writing in", which is a bad way of using "@here" since there no way for users to specify whether they "want to be notified for @here here" (without disabling @everyone as well, and in this case it's not what they want) =/

I believe it would be good to rename "@here" into something more clear about how it works, like "@online" (or maybe keep both and set "@here" to have a channel-wise opt-out ping effect?)

I'm sure it would also clear out all the feedbacks on this site revolving around "Please split up @everyone and @here notification disabling" =)