Fix Missing imports in openai-harmony.md example code

Author: Howe829

articles/openai-harmony.md

@@ -126,18 +126,20 @@ Additionally the openai_harmony library also includes a StreamableParser for par
 ```py
 from openai_harmony import (
     load_harmony_encoding,
-    StreamableParser
+    Role,
+    StreamableParser,
+    HarmonyEncodingName
 )
-
+ 
 encoding = load_harmony_encoding(HarmonyEncodingName.HARMONY_GPT_OSS)
 stream = StreamableParser(encoding, role=Role.ASSISTANT)
-
+ 
 tokens = [
     200005,35644,200008,1844,31064,25,392,4827,382,220,17,659,220,17,16842,12295,81645,
     13,51441,6052,13,200007,200006,173781,200005,17196,200008,17,659,220,17,314,220,19,
     13,200002
 ]
-
+ 
 for token in tokens:
     stream.process(token)
     print("--------------------------------")