Clarify input_output_aliases indexing in pallas_call.

PiperOrigin-RevId: 800063159

Author: Google-ML-Automation

jax/_src/pallas/pallas_call.py

@@ -1556,7 +1556,7 @@ def pallas_call(
       etc.
     input_output_aliases: a dictionary mapping the index of some inputs to
       the index of the output that aliases them. These indices are in the
-      flattened inputs and outputs.
+      flattened inputs and outputs (ignoring None values).
     debug: if True, Pallas prints various intermediate forms of the kernel
       as it is being processed.
     interpret: runs the ``pallas_call`` as a ``jax.jit`` of a scan over the