Add release note

Style fixes

Author: ElePT

qiskit_ibm_runtime/circuit/library/mid_circuit_measure.py

@@ -10,11 +10,19 @@
 # copyright notice, and modified files need to carry a notice indicating
 # that they have been altered from the originals.
 
+"""MidCircuitMeasure gate."""
+
 from qiskit.circuit import Instruction
 
 
 class MidCircuitMeasure(Instruction):
-    def __init__(self, name="measure_2", label=None):
+    """
+    This instruction implements an alternative 'named' measurement definition
+    (1 classical bit, 1 quantum bit), whose name can be used to map to a corresponding
+    mid-circuit measurement instruction implementation on hardware.
+    """
+
+    def __init__(self, name: str = "measure_2", label: str = None) -> None:
         if not name.startswith("measure_"):
             raise ValueError(
                 "Invalid name for mid-circuit measure instruction."

release-notes/unreleased/2316.feat.rst

@@ -0,0 +1,9 @@
+The `qiskit-ibm-runtime` package has been extended with two new modules: :mod:`.circuit` and 
+:mod:`.circuit.library`. These modules are designed to mirror the structure of the 
+corresponding `qiskit` SDK modules, while providing vendor-specific implementations of 
+circuit objects and instructions.
+
+The first addition to this new circuit library is the :class:`.MidCircuitMeasure` class. 
+This class enables the creation of instructions that follow the naming convention 
+`measure_<identifier>`, which are mapped to specific mid-circuit measurement
+ hardware instructions matching that pattern.