Fixed doc

Closes #438

Author: crmne

docs/_getting_started/overview.md

@@ -147,8 +147,7 @@ chat = RubyLLM.chat(model: "{{ site.models.default_chat }}")  # Uses OpenAI
 # Explicit provider
 chat = RubyLLM.chat(
   model: "{{ site.models.local_llama }}",
-  provider: "ollama",
-  base_url: "http://localhost:11434"
+  provider: :ollama,
 )
 ```
 
@@ -191,4 +190,4 @@ Now that you understand how RubyLLM works, you're ready to dive deeper into spec
 3. Explore [Tools and Function Calling]({% link _core_features/tools.md %}) to give AI access to your code
 4. For Rails developers, the [Rails Integration]({% link _advanced/rails.md %}) guide covers database persistence and real-time features
 
-Each guide builds on the concepts introduced here, gradually revealing more advanced features as you need them.
+Each guide builds on the concepts introduced here, gradually revealing more advanced features as you need them.