docs: use double backticks in release note for reno RST check

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: chuenchen309

releasenotes/notes/chatmsg-from-openai-dict-f15b50d38bdf9abb.yaml

@@ -1,5 +1,5 @@
 ---
 enhancements:
   - |
-    Add the `from_openai_dict_format` class method to the `ChatMessage` class. It allows you to create a `ChatMessage`
+    Add the ``from_openai_dict_format`` class method to the ``ChatMessage`` class. It allows you to create a ``ChatMessage``
     from a dictionary in the format expected by OpenAI's Chat API.