docs: fix minor spelling issue

1. "to ensure that the examples from the traing set don't feature within the test set." -> "to ensure that the examples from the training set don't feature within the test set."

examples/fine-tuned_qa/olympics-3-train-qa.ipynb

@@ -228,7 +228,7 @@
     "\n",
     "This process is noisy, as sometimes the question might be answerable given a different context, but on average we hope this won't affect the peformance too much.\n",
     "\n",
-    "We apply the same process of dataset creation for both the discriminator, and the Q&A answering model. We apply the process separately for the training and testing set, to ensure that the examples from the traing set don't feature within the test set."
+    "We apply the same process of dataset creation for both the discriminator, and the Q&A answering model. We apply the process separately for the training and testing set, to ensure that the examples from the training set don't feature within the test set."
    ]
   },
   {