message: Fix related doc clarification request on tf.contrib.lookup.MutableHashTable insert operation
  Make the doc example executable, and explicitly suggests that MutableDenseHashTable.insert is an operation rather than in-place computation.
diff: @@ -494,7 +494,7 @@ class MutableDenseHashTable(LookupInterface):
  value_dtype=tf.int64,
  default_value=-1,
  empty_key=0)
  - table.insert(keys, values)
  + sess.run(table.insert(keys, values))
  out = table.lookup(query_keys)
  print(out.eval())
  ```
  