Cherry pick fix acc sample code bug (#30716)

* Alias from  paddle.fluid.layers.auc to paddle.static.auc (#30206)

* add alias from  fluid.layers.auc to static.auc

* Update __init__.py

* add auc into all list

* alias acc, expose to users

* add auc into 'all' list (#30310)

* add auc into 'all' list

* alias acc, expose to users

* update sample code

* fix paddle.static.acc and auc sample code bug, test=document_fix

python/paddle/fluid/layers/metric_op.py

@@ -51,6 +51,7 @@ def accuracy(input, label, k=1, correct=None, total=None):
 
     Examples:
         .. code-block:: python
+
             import numpy as np
 
             import paddle
@@ -156,6 +157,7 @@ def auc(input,
 
     Examples:
         .. code-block:: python
+
             import numpy as np
 
             import paddle