message: Convert to code blocks, so it renders in api_docs
diff: @@ -223,6 +223,7 @@ class Interpreter(object):
  Usage:
  + ```
  interpreter.allocate_tensors()
  input = interpreter.tensor(interpreter.get_input_details()[0]["index"])
  output = interpreter.tensor(interpreter.get_output_details()[0]["index"])
  @@ -230,6 +231,7 @@ class Interpreter(object):
  input().fill(3.)
  interpreter.invoke()
  print("inference %s" % output())
  + ```
  Notice how this function avoids making a numpy array directly. This is
  because it is important to not hold actual numpy views to the data longer
  @@ -240,12 +242,14 @@ class Interpreter(object):
  WRONG:
  + ```
  input = interpreter.tensor(interpreter.get_input_details()[0]["index"])()
  output = interpreter.tensor(interpreter.get_output_details()[0]["index"])()
  interpreter.allocate_tensors() # This will throw RuntimeError
  for i in range(10):
  input.fill(3.)
  interpreter.invoke() # this will throw RuntimeError since input,output
  + ```
  Args:
  tensor_index: Tensor index of tensor to get. This value can be gotten from
  