fix typo (#11689)

qiskit/transpiler/passes/synthesis/plugin.py

@@ -216,7 +216,7 @@ def run(self, high_level_object, coupling_map=None, target=None, qubits=None, **
 :class:`~qiskit.transpiler.passes.synthesis.plugin.HighLevelSynthesisPlugin` as
 a setuptools entry point in the package metadata. This is done by adding
 an ``entry-points`` table in ``pyproject.toml`` for the plugin package with the necessary entry
-points under the ``qiskit.unitary_synthesis`` namespace. For example:
+points under the ``qiskit.synthesis`` namespace. For example:
 
 .. code-block:: toml