Update simulation_visualisation/simulation_visualisation.ipynb

Co-authored-by: Alyssa Travitz <31974495+atravitz@users.noreply.github.com>

Author: jthorton

simulation_visualisation/simulation_visualisation.ipynb

@@ -256,7 +256,7 @@
    "id": "75602d58-6709-4d9b-8a52-9896fdc6a0af",
    "metadata": {},
    "source": [
-    "## Centring the Ligand with `mdtraj`\n",
+    "## Centering the Ligand with `mdtraj`\n",
     "\n",
     "You may have noticed in the view above that the ligand seems to have drifted away from the protein, this is a visualisation artifact caused by the use of periodic boundary conditions and the way in which `OpenMM` tries to ensure that all particle positions are written into a single periodic box. We can fix this, however, using `mdtraj` and the [image_molecules](https://mdtraj.org/1.9.3/api/generated/mdtraj.Trajectory.html?highlight=image_molecules#mdtraj.Trajectory.image_molecules) function:"
    ]