Add additional description to perturbation tutorial

Author: Sebastian Birk

docs/tutorials/notebooks/nb4_demo_insilico_perturbation.ipynb

@@ -226,7 +226,7 @@
    "source": [
     "## 5. Make a modified (i.e. perturbed) version of the tissue\n",
     "Here we perturb the tissue by altering some of its cell type labels and obtain the \"Modified tissue\" described above in the overview section.\n",
-    "Note that this perturbation is for demonstraion only rather than getting biologically meaningful results."
+    "Note that this perturbation is for demonstration only rather than getting biologically meaningful results. It is also possible to perform other perturbations, e.g. deleting cells, by modifying the AnnData object accordingly. "
    ]
   },
   {
@@ -1153,7 +1153,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.10.12"
+   "version": "3.10.15"
   }
  },
  "nbformat": 4,