Fix quantumlib#5497

Removed mention of `decompose_operation`.

Issue quantumlib#5497 talks about updating the IonQ documentation to describe
the use of transformers for compilation introduced in quantumlib#5479. This
commit does not address that.

Author: mhucka

Diff for: docs/hardware/ionq/circuits.md

@@ -96,12 +96,12 @@ these gates are one or two qubit gates which support the `unitary` protocol
 for the gate), there is support for compiling these into API supported gates.
 This conversion may not be optimal, but it does produce a valid API circuit.
 
-This support is given by the `cirq_ionq.IonQAPIDevice` and its
-`decompose_operation` method.  On way to use this is to pass the device
+This support is given by the `cirq_ionq.IonQAPIDevice`.
+On way to use this is to pass the device
 to a circuit, and these decompositions will be automatically applied while
 the circuit is being constructed:
-python
-```
+
+```python
 q0 = cirq.LineQubit(0)
 device = ionq.IonQAPIDevice([q0])
 circuit = cirq.Circuit(device=device)
@@ -121,4 +121,3 @@ circuit.
 [How to use the service API](jobs.md)
 
 [Get information about QPUs from IonQ calibrations](calibrations.md)
-