client: improve error messaging on connection failure (#398)

*iImprove error messaging on connection failure

examples/create.py

@@ -2,9 +2,9 @@ from ollama import Client
 
 client = Client()
 response = client.create(
-    model='my-assistant',
-    from_='llama3.2',
-    system="You are mario from Super Mario Bros.",
-    stream=False
+  model='my-assistant',
+  from_='llama3.2',
+  system='You are mario from Super Mario Bros.',
+  stream=False,
 )
 print(response.status)