docs: Update blocks formatting in docs/source files (#3120)

**Description:** 
The standard markdown [!NOTE] format is not supported on Sphinx
generated documentation, replacing those instances. Also updating other
Notes, Tips and Warning blocks throughout the source docs

WIP: Working to update the provider code gen

docs/source/building_applications/responses_vs_agents.md

@@ -2,7 +2,9 @@
 
 Llama Stack (LLS) provides two different APIs for building AI applications with tool calling capabilities: the **Agents API** and the **OpenAI Responses API**. While both enable AI systems to use tools, and maintain full conversation history, they serve different use cases and have distinct characteristics.
 
-> **Note:** For simple and basic inferencing, you may want to use the [Chat Completions API](https://llama-stack.readthedocs.io/en/latest/providers/index.html#chat-completions) directly, before progressing to Agents or Responses API.
+```{note}
+For simple and basic inferencing, you may want to use the [Chat Completions API](https://llama-stack.readthedocs.io/en/latest/providers/index.html#chat-completions) directly, before progressing to Agents or Responses API.
+```
 
 ## Overview
 

docs/source/building_applications/tools.md

@@ -76,7 +76,9 @@ Features:
 - Context retrieval with token limits
 
 
-> **Note:** By default, llama stack run.yaml defines toolgroups for web search, wolfram alpha and rag, that are provided by tavily-search, wolfram-alpha and rag providers.
+```{note}
+By default, llama stack run.yaml defines toolgroups for web search, wolfram alpha and rag, that are provided by tavily-search, wolfram-alpha and rag providers.
+```
 
 ## Model Context Protocol (MCP)