docs: typo in tf qa example (#31864)

Signed-off-by: chenk <hen.keinan@gmail.com>

examples/tensorflow/question-answering/README.md

@@ -21,6 +21,7 @@ For straightforward use-cases you may be able to use this script without modific
 included comments in the code to indicate areas that you may need to adapt to your own projects.
 
 ### Usage notes
+
 Note that when contexts are long they may be split into multiple training cases, not all of which may contain
 the answer span.
 
@@ -45,11 +46,12 @@ README, but for more information you can see the 'Input Datasets' section of
 [this document](https://www.tensorflow.org/guide/tpu).
 
 ### Example command
+
 ```bash
 python run_qa.py \
 --model_name_or_path distilbert/distilbert-base-cased \
 --output_dir output \
 --dataset_name squad \
 --do_train \
---do_eval \
+--do_eval
 ```