docs(middleware): update single code blocks to title

Author: heitorlessa

docs/utilities/middleware_factory.md

@@ -18,96 +18,78 @@ You can create your own middleware using `lambda_handler_decorator`. The decorat
 * **event** - Lambda function invocation event
 * **context** - Lambda function context object
 
-=== "app.py"
+```python hl_lines="3-4 10" title="Creating your own middleware for before/after logic"
+from aws_lambda_powertools.middleware_factory import lambda_handler_decorator
 
-    ```python hl_lines="3-4 10"
-    from aws_lambda_powertools.middleware_factory import lambda_handler_decorator
+@lambda_handler_decorator
+def middleware_before_after(handler, event, context):
+	# logic_before_handler_execution()
+	response = handler(event, context)
+	# logic_after_handler_execution()
+	return response
 
-    @lambda_handler_decorator
-    def middleware_before_after(handler, event, context):
-        # logic_before_handler_execution()
-        response = handler(event, context)
-        # logic_after_handler_execution()
-        return response
-
-    @middleware_before_after
-    def lambda_handler(event, context):
-        ...
-    ```
+@middleware_before_after
+def lambda_handler(event, context):
+	...
+```
 
 ## Middleware with params
 
 You can also have your own keyword arguments after the mandatory arguments.
 
-=== "app.py"
-
-    ```python hl_lines="2 12"
-    @lambda_handler_decorator
-    def obfuscate_sensitive_data(handler, event, context, fields: List = None):
-        # Obfuscate email before calling Lambda handler
-        if fields:
-            for field in fields:
-                if field in event:
-                    event[field] = obfuscate(event[field])
+```python hl_lines="2 12" title="Accepting arbitrary keyword arguments"
+@lambda_handler_decorator
+def obfuscate_sensitive_data(handler, event, context, fields: List = None):
+	# Obfuscate email before calling Lambda handler
+	if fields:
+		for field in fields:
+			if field in event:
+				event[field] = obfuscate(event[field])
 
-        return handler(event, context)
+	return handler(event, context)
 
-    @obfuscate_sensitive_data(fields=["email"])
-    def lambda_handler(event, context):
-        ...
-    ```
+@obfuscate_sensitive_data(fields=["email"])
+def lambda_handler(event, context):
+	...
+```
 
 ## Tracing middleware execution
 
 If you are making use of [Tracer](../core/tracer.md), you can trace the execution of your middleware to ease operations.
 
 This makes use of an existing Tracer instance that you may have initialized anywhere in your code.
 
-=== "trace_middleware_execution.py"
+```python hl_lines="3" title="Tracing custom middlewares with Tracer"
+from aws_lambda_powertools.middleware_factory import lambda_handler_decorator
 
-    ```python hl_lines="3"
-    from aws_lambda_powertools.middleware_factory import lambda_handler_decorator
+@lambda_handler_decorator(trace_execution=True)
+def my_middleware(handler, event, context):
+	return handler(event, context)
 
-    @lambda_handler_decorator(trace_execution=True)
-    def my_middleware(handler, event, context):
-        return handler(event, context)
-
-    @my_middleware
-    def lambda_handler(event, context):
-        ...
-    ```
+@my_middleware
+def lambda_handler(event, context):
+	...
+```
 
 When executed, your middleware name will [appear in AWS X-Ray Trace details as](../core/tracer.md) `## middleware_name`.
 
 For advanced use cases, you can instantiate [Tracer](../core/tracer.md) inside your middleware, and add annotations as well as metadata for additional operational insights.
 
-=== "app.py"
-
-    ```python hl_lines="6-8"
-    from aws_lambda_powertools.middleware_factory import lambda_handler_decorator
-    from aws_lambda_powertools import Tracer
+```python hl_lines="6-8" title="Add custom tracing insights before/after in your middlware"
+from aws_lambda_powertools.middleware_factory import lambda_handler_decorator
+from aws_lambda_powertools import Tracer
 
-    @lambda_handler_decorator(trace_execution=True)
-    def middleware_name(handler, event, context):
-        tracer = Tracer() # Takes a copy of an existing tracer instance
-        tracer.add_annotation...
-        tracer.add_metadata...
-        return handler(event, context)
-    ```
+@lambda_handler_decorator(trace_execution=True)
+def middleware_name(handler, event, context):
+	# tracer = Tracer() # Takes a copy of an existing tracer instance
+	# tracer.add_annotation...
+	# tracer.add_metadata...
+	return handler(event, context)
+```
 
 ## Tips
 
 * Use `trace_execution` to quickly understand the performance impact of your middlewares, and reduce or merge tasks when necessary
 * When nesting multiple middlewares, always return the handler with event and context, or response
 * Keep in mind [Python decorators execution order](https://realpython.com/primer-on-python-decorators/#nesting-decorators){target="_blank"}. Lambda handler is actually called once (top-down)
 * Async middlewares are not supported
-
-## Testing your code
-
-When unit testing middlewares with `trace_execution` option enabled, use `POWERTOOLS_TRACE_DISABLED` env var to safely disable Tracer.
-
-=== "shell"
-
-    ```bash
-    POWERTOOLS_TRACE_DISABLED=1 python -m pytest
-    ```