x/build/cmd/gopherbot: reply when a command is not understood

[josharian]

Broken out from some other recent issue (#27961 (comment)), a suggestion from @bradfitz: if @gopherbot doesn't understand a request (e.g. because a human substituted a synonym for one of the magic commands), it should reply and say so.

cc @FiloSottile @dmitshur

[dmitshur]

What's the criteria for @gopherbot to consider a comment to be a request?

Should it be a comment that mentions @gopherbot and also contains "please"? Or just the mention on its own?

[josharian]

I'd say "please" is the magic word. :) Maybe "please" in the same sentence/line.