docs: resolve rendering issue with code block in getting started docs (…

…#754)

[fix] - resolve issue with code block rendering

docs/docs/getting-started/guide-openai.mdx

@@ -14,8 +14,8 @@ Dive right into executing your first program utilizing LangChainGo in tandem wit
 ## Steps
 
 1. **Set up your OpenAI API Key**: Before interacting with the OpenAI API, ensure that you've set up your API key. Typically, this is done by setting an environment variable. In your terminal, run the command:
-   ```shell
-   export OPENAI_API_KEY=your_openai_api_key_here
+```shell
+export OPENAI_API_KEY=your_openai_api_key_here
 ```
 
 2. Run the Example: Execute the following command: