Add PLUGIN_TYPE to markov.py

Forgot to add this, whoopsie

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

plugins/markov.py

@@ -140,3 +140,6 @@ class Markov(Plugin):
 
     async def on_unload(self, conn: IrcProtocol):
         self.save()
+
+
+PLUGIN_TYPE = Markov