Update docs/advanced.rst

Co-authored-by: Luke Mitchell <94070284+lujamitch@users.noreply.github.com>

Author: ojii

docs/advanced.rst

@@ -84,7 +84,7 @@ Some simple monitoring strategies are provided built in, but you can implement y
 
     .. py:attribute:: decrement
 
-        Decrement the failure count by on on success.
+        Decrement the failure count by one on success.
 
     .. py:attribute:: reset