Filter out "+1" messages from issue streams

**User Story: **

Isabelle the Issue commentor has added valuable information to an issue. Vern the voter has voted on this issue as well. Both are now subscribed to get updates.

Victor the vaccuous commentor and 50 more like him, comment: "+1!" being either unaware of voting, unaware that he's spamming the entire list, or uninterested in the annoyance it causes.

Isabelle, and Vern are annoyed and decide to stop participating.

Potential solutions:

• It would be nice to be able to automatically block, filter, or moderate comments which match a certain pattern to avoid the spam.
• Alternatively it might work to warn users:

• • when commenting and the watch list is over a certain size "comment will be sent to 103 people, are you sure you want to post?"
  • as they type if they use certain phrases including "+1" that are considered noise: "+1 no longer functions for voting. Please use the vote functionality instead"