[commands] Added a method to reset command cooldown.

discord/ext/commands/cooldowns.py

@@ -43,6 +43,7 @@ class Cooldown:
         self.type = type
         self._window = 0.0
         self._tokens = self.rate
+        self._last = 0.0
 
         if not isinstance(self.type, BucketType):
             raise TypeError('Cooldown type must be a BucketType')
@@ -72,6 +73,10 @@ class Cooldown:
         if self._tokens == 0:
             self._window = current
 
+    def reset(self):
+        self._tokens = self.rate
+        self._last = 0.0
+
     def copy(self):
         return Cooldown(self.rate, self.per, self.type)