Fix phi model doc checkpoint (#28581)

Co-authored-by: Pashmina Cameron <11311835+pashminacameron@users.noreply.github.com>

docs/source/en/model_doc/phi.md

@@ -84,8 +84,8 @@ Phi-2 has been integrated in the development version (4.37.0.dev) of `transforme
 ```python
 >>> from transformers import AutoModelForCausalLM, AutoTokenizer
 
->>> model = AutoModelForCausalLM.from_pretrained("phi-2")
->>> tokenizer = AutoTokenizer.from_pretrained("phi-2")
+>>> model = AutoModelForCausalLM.from_pretrained("microsoft/phi-2")
+>>> tokenizer = AutoTokenizer.from_pretrained("microsoft/phi-2")
 
 >>> inputs = tokenizer('Can you help me write a formal email to a potential business partner proposing a joint venture?', return_tensors="pt", return_attention_mask=False)