Update tidy3d/components/mode_spec.py

Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>

Author: dmarek-flex

tidy3d/components/mode_spec.py

@@ -256,7 +256,7 @@ def check_microwave_mode_spec_consistent(cls, val, values):
 
         if not valid_number_impedance_specs:
             raise SetupError(
-                f"Given {val.num_impedance_specs} impedance specifications in the 'MicrowaveModeSpec, "
+                f"Given {val.num_impedance_specs} impedance specifications in the 'MicrowaveModeSpec', "
                 f"but the number of modes requested is {num_modes}. Please either ensure that the "
                 "number of impedance specifications is equal to the number of modes or leave the "
                 "'MicrowaveModeSpec' field as 'None', if impedances are not needed."