server types: Move 'model' parameter to clarify it is used

The 'model' parameter has been supported since abetlen#931. Its placement in this section was copied from an older version of the file, and hasn't been corrected since.

Correcting this will make it clearer what parameters are supported by llama-cpp-python.

Author: domdomegg

llama_cpp/server/types.py

@@ -107,6 +107,7 @@
 
 
 class CreateCompletionRequest(BaseModel):
+    model: Optional[str] = model_field
     prompt: Union[str, List[str]] = Field(
         default="", description="The prompt to generate completions for."
     )
@@ -138,7 +139,6 @@ class CreateCompletionRequest(BaseModel):
     seed: Optional[int] = Field(None)
 
     # ignored or currently unsupported
-    model: Optional[str] = model_field
     n: Optional[int] = 1
     best_of: Optional[int] = 1
     user: Optional[str] = Field(default=None)
@@ -190,6 +190,7 @@ class ChatCompletionRequestMessage(BaseModel):
 
 
 class CreateChatCompletionRequest(BaseModel):
+    model: Optional[str] = model_field
     messages: List[llama_cpp.ChatCompletionRequestMessage] = Field(
         default=[], description="A list of messages to generate completions for."
     )
@@ -237,7 +238,6 @@ class CreateChatCompletionRequest(BaseModel):
     )
 
     # ignored or currently unsupported
-    model: Optional[str] = model_field
     n: Optional[int] = 1
     user: Optional[str] = Field(None)