Fix typo in zero_to_thunder.ipynb (#1308)

notebooks/zero_to_thunder.ipynb

@@ -180,7 +180,7 @@
    "source": [
     "So what has changed? Quite a bit!\n",
     "\n",
-    "When we call the Thunder module, it do the computation in a single function without control flow. And what's more, it applies optimizations, such as creating fusions for NVFuser to execute. We can see all this by showing the last computation trace:"
+    "When we call the Thunder module, it does the computation in a single function without control flow. And what's more, it applies optimizations, such as creating fusions for NVFuser to execute. We can see all this by showing the last computation trace:"
    ]
   },
   {