fix typo (#2532)

1) Any breaking changes  ?
None

2) What does this do ?
Fix typo in QA eval

cc @hwchase17

docs/use_cases/evaluation/question_answering.ipynb

@@ -130,7 +130,7 @@
    "source": [
     "## Evaluation\n",
     "\n",
-    "We can see that if we tried to just do exact match on the answer answers (`11` and `No`) they would not match what the lanuage model answered. However, semantically the language model is correct in both cases. In order to account for this, we can use a language model itself to evaluate the answers."
+    "We can see that if we tried to just do exact match on the answer answers (`11` and `No`) they would not match what the language model answered. However, semantically the language model is correct in both cases. In order to account for this, we can use a language model itself to evaluate the answers."
    ]
   },
   {