Fix f-string calls (#7243)

* treewide: remove extraneous string breaks

* Fix formatting

Co-authored-by: Jake Lishman <jake.lishman@ibm.com>

qiskit/circuit/library/generalized_gates/pauli.py

@@ -71,7 +71,9 @@ def validate_parameter(self, parameter):
                 return parameter
             else:
                 raise CircuitError(
-                    "Parameter string {0} should contain only 'I', 'X', 'Y', 'Z' characters"
+                    f"Parameter string {parameter} should contain only 'I', 'X', 'Y', 'Z' characters"
                 )
         else:
-            raise CircuitError("Parameter {0} should be a string of 'I', 'X', 'Y', 'Z' characters")
+            raise CircuitError(
+                f"Parameter {parameter} should be a string of 'I', 'X', 'Y', 'Z' characters"
+            )

qiskit/circuit/register.py

@@ -113,7 +113,7 @@ def __init__(self, size=None, name=None, bits=None):
         if bits is not None:
             # pylint: disable=isinstance-second-argument-not-valid-type
             if any(not isinstance(bit, self.bit_type) for bit in bits):
-                raise CircuitError("Provided bits did not all match register type. bits=%s" % bits)
+                raise CircuitError(f"Provided bits did not all match register type. bits={bits}")
             self._bits = list(bits)
             self._bit_indices = {bit: idx for idx, bit in enumerate(self._bits)}
         else: