docs: improve tool documentation and examples

- Update SerperDevTool documentation with accurate parameters and JSON response format
- Enhance XMLSearchTool and MDXSearchTool docs with RAG capabilities and required parameters
- Fix code block formatting across multiple tool documentation files
- Add clarification about environment variables and configuration
- Validate all examples against actual implementations
- Successfully tested with mkdocs build

Co-Authored-By: Joe Moura <joao@crewai.com>

docs/tools/codeinterpretertool.mdx

@@ -31,7 +31,7 @@ Remember that when using this tool, the code must be generated by the Agent itse
 The code must be a Python3 code. And it will take some time for the first time to run 
 because it needs to build the Docker image.
 
-```python Code
+```python
 from crewai import Agent
 from crewai_tools import CodeInterpreterTool
 
@@ -43,7 +43,7 @@ Agent(
 
 We also provide a simple way to use it directly from the Agent.
 
-```python Code
+```python
 from crewai import Agent
 
 agent = Agent(