FIX: Wrong discobot tutorial started for certain locales.

If a locale has triggers that start with the same word, our regexp will
always end up matching the first trigger. For example,

`start tutorial` and `start tutorial advanced`

To support the change, we have to make the match on triggers more
restrictive. `@discobot quote here` will no longer work like `@discobot
quote`.

plugins/discourse-narrative-bot/lib/discourse_narrative_bot/track_selector.rb

@@ -227,7 +227,7 @@ module DiscourseNarrativeBot
 
     def match_trigger?(trigger)
       discobot_username = self.discobot_user.username
-      regexp = Regexp.new("<a class=\"mention\".*>@#{discobot_username}</a> #{trigger}", 'i')
+      regexp = Regexp.new("<a class=\"mention\".*>@#{discobot_username}</a> #{trigger}</p>", 'i')
       match = @post.cooked.match(regexp)
 
       if @is_pm_to_bot