Add support for GPT-5 models in documentation

Author: kalanchan

docs/cody/capabilities/supported-models.mdx

@@ -8,6 +8,9 @@ Cody supports a variety of cutting-edge large language models for use in chat an
 
 | **Provider** |                                                                   **Model**                                                                   |    **Status**    |
 | :----------- | :-------------------------------------------------------------------------------------------------------------------------------------------- | :--------------- |
+| OpenAI       | [GPT-5](https://platform.openai.com/docs/models/gpt-5)                                                                                        | ✅                |
+| OpenAI       | [GPT-5-mini](https://platform.openai.com/docs/models/gpt-5-mini)                                                                              | ✅                |
+| OpenAI       | [GPT-5-nano](https://platform.openai.com/docs/models/gpt-5-nano)                                                                              | ✅                |
 | OpenAI       | [GPT-4 Turbo](https://platform.openai.com/docs/models/gpt-4-and-gpt-4-turbo#:~:text=TRAINING%20DATA-,gpt%2D4%2D0125%2Dpreview,-New%20GPT%2D4) | ✅                |
 | OpenAI       | [GPT-4o](https://platform.openai.com/docs/models#gpt-4o)                                                                                      | ✅                |
 | OpenAI       | [GPT-4o-mini](https://platform.openai.com/docs/models#gpt-4o-mini)                                                                            | ✅                |