Don't Make Hashtags Which Aren't Channels Clickable

[graywolf336]

Others might disagree with this, but I feel that if a word after a hashtag isn't a channel that exists then it shouldn't be clickable. This way people can use hashtags without others thinking they're talking about a channel if it doesn't exist.

[Morgul]

I agree. It confused me the other day to see rocketbot display a github comment talking about issue #45, with the #45 clickable, but not taking me to the github issue.