[GPT2] Correct typo in docs (#6352)

src/transformers/configuration_gpt2.py

@@ -71,7 +71,7 @@ class GPT2Config(PretrainedConfig):
                 The dropout ratio for the attention.
             layer_norm_epsilon (:obj:`float`, optional, defaults to 1e-5):
                 The epsilon to use in the layer normalization layers
-            initializer_range (:obj:`float`, optional, defaults to 16):
+            initializer_range (:obj:`float`, optional, defaults to 0.02):
                 The standard deviation of the truncated_normal_initializer for initializing all weight matrices.
             summary_type (:obj:`string`, optional, defaults to "cls_index"):
                 Argument used when doing sequence summary. Used in for the multiple choice head in