Apply suggested fix to notebooks/workflow_3_cascaded_mzi.ipynb from Copilot Autofix

Co-authored-by: Copilot Autofix powered by AI <223894421+github-code-quality[bot]@users.noreply.github.com>

Author: nikosavola

notebooks/workflow_3_cascaded_mzi.ipynb

@@ -11,7 +11,7 @@
     "\n",
     "Each filter stage is formed by 4 cascaded Mach-Zenhder Interferometers (MZIs) with predefined delays for the central wavelength.  Symmetrical Direction Couplers (DCs) are used to mix the signals at the ends of the MZI arms.  In order to facilitate fabrication, all DC gaps are kept equal, so the power transfer ratios are defined by the coupling length of the DCs.\n",
     "\n",
-    "We will design each DC through 3D FDTD simulations to guarantee the desired power ratios, which have been calculated to provide maximally flat response.  The S parameters computed through FDTD are later used in the full circuit simulation along with models for staight and curved waveguide sections, leading to an accurate model that exhibits features similar to those found in experimental data."
+    "We will design each DC through 3D FDTD simulations to guarantee the desired power ratios, which have been calculated to provide maximally flat response.  The S parameters computed through FDTD are later used in the full circuit simulation along with models for straight and curved waveguide sections, leading to an accurate model that exhibits features similar to those found in experimental data."
    ]
   },
   {