Remove the nickname in parentheses at end of messages optionally

[sckott]

e.g., sckott/testhey#1 (comment)

since we now us a separate github account of name ropenscibot we no longer need the (ropensci-bot) at the end of the message - could have a toggle for that, or could possibly move to employing templates for messages like

... message ... {{emoji}}  ( {{nickname}} )

so the emoji is user specified and the nickname can be specified or left blank