Clarify move acceptance probability. [ci skip]

Author: lohedges

src/loch/_sampler.py

@@ -1041,7 +1041,8 @@ def water_state(self) -> _np.ndarray:
 
     def move_acceptance_probability(self) -> float:
         """
-        Return the acceptance probability.
+        Return the acceptance probability. Note that this can be greater than
+        1, since multiple insertions/deletions can be accepter per move.
 
         Returns
         -------