Apply suggestions from code review

Co-authored-by: Julien Gacon <[email protected]>

qiskit/circuit/__init__.py

@@ -1057,7 +1057,7 @@ def __array__(self, dtype=None, copy=None):
 Hamiltonian, i.e. incorrect unitary evolution, or errors from incorrect temporal control of the
 quantum system, which includes things like incorrect pulse-shapes for gates.
 
-Pauli-twirling is a quantum error suppression technique that uses randomization to shape coherent
+Pauli twirling is a quantum error suppression technique that uses randomization to shape coherent
 error into stochastic errors by combining the results from many random, but logically equivalent
 circuits, together. Qiskit provides a function to apply Pauli twirling to a given circuit for
 standard two qubit gates.

qiskit/circuit/twirling.py

@@ -48,9 +48,9 @@ def twirl_circuit(
         twirling_gate: The gate to twirl, defaults to `None` which means twirl all default gates:
             :class:`.CXGate`, :class:`.CZGate`, :class:`.ECRGate`, and :class:`.iSwapGate`.
             If supplied it can either be a single gate or a list of gates either as either a gate
-            object or it's string name. Currently only the names `"cx"`, `"cz"`, `"ecr"`,  and
+            object or its string name. Currently only the names `"cx"`, `"cz"`, `"ecr"`,  and
             `"iswap"` are supported. If a gate object is provided outside the default gates it must
-            have a matrix defined from it's :class:`~.Gate.to_matrix` method for the gate to potentially
+            have a matrix defined from its :class:`~.Gate.to_matrix` method for the gate to potentially
             be twirled. If a valid twirling configuration can't be computed that particular gate will
             be silently ignored and not twirled.
         seed: An integer seed for the random number generator used internally.