fix small bug of error message for elementwise_add and elementwise_mul (#20619)

* fix error message for elementwise_add/mul;test=develop

* fix type error message;test=develop

python/paddle/fluid/layers/nn.py

@@ -13772,24 +13772,24 @@ def _elementwise_op(helper):
             (op_type, type(y)))
     if convert_dtype(x.dtype) in ['float16']:
         warnings.warn(
-            "The data type of 'x' in batch_norm only support float16 on GPU now."
-        )
+            "The data type of 'x' in %s only support float16 on GPU now." %
+            (op_type))
     if convert_dtype(y.dtype) in ['float16']:
         warnings.warn(
-            "The data type of 'y' in batch_norm only support float16 on GPU now."
-        )
+            "The data type of 'y' in %s only support float16 on GPU now." %
+            (op_type))
     if convert_dtype(x.dtype) not in [
             'float16', 'float32', 'float64', 'int32', 'int64'
     ]:
         raise TypeError(
-            "The data type of 'x' in batch_norm must be float16 or float32 or float64 or int32 or int64, but received %s."
-            % (convert_dtype(x.dtype)))
+            "The data type of 'x' in %s must be float16 or float32 or float64 or int32 or int64, "
+            "but received %s." % (op_type, convert_dtype(x.dtype)))
     if convert_dtype(y.dtype) not in [
             'float16', 'float32', 'float64', 'int32', 'int64'
     ]:
         raise TypeError(
-            "The data type of 'y' in batch_norm must be float16 or float32 or float64 or int32 or int64, but received %s."
-            % (convert_dtype(y.dtype)))
+            "The data type of 'y' in %s must be float16 or float32 or float64 or int32 or int64, "
+            "but received %s." % (op_type, convert_dtype(y.dtype)))
 
     axis = helper.kwargs.get('axis', -1)
     use_mkldnn = helper.kwargs.get('use_mkldnn', False)