update docs and debugging info (Azure#33111)

* update docs and debugging info

* Update doc/dev/code_snippets.md

Co-authored-by: Krista Pratico <[email protected]>

---------

Co-authored-by: Krista Pratico <[email protected]>

Author: xiangyan99

doc/dev/code_snippets.md

@@ -10,6 +10,8 @@ All code snippets in README should be up to date and runnable. And we want to ha
 
 Samples need to store in the samples folder under each service. In each sample file, we use `# [START snippet_name]` & `# [END snippet_name]` to note a code snippet.
 
+**Note:** valid characters for a snippet name are [A-Z a-z0-9_]
+
 A sample code snippet could be like:
 
 ```python
@@ -25,18 +27,28 @@ https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/core/azure-core/samp
 
 ## Refer samples
 
-Instead of copying the code snippet into README which is hard to maintain and validate, we add reference to the sample snippet in README. We use the annotation <!-- SNIPPET:file_name.snippet_name--> to refer the code snippet in README file.
+Instead of copying the code snippet into README which is hard to maintain and validate, we add reference to the sample snippet in README. We use the annotation `\<!-- SNIPPET:file_name.snippet_name-->` to refer the code snippet in README file.
 
 It is like:
 
-<!-- SNIPPET:test_example_async.asyncio -->
+`\<!-- SNIPPET:test_example_async.asyncio -->`
+
 ```python
 from azure.core.pipeline.transport import AsyncioRequestsTransport
 
 async with AsyncPipeline(AsyncioRequestsTransport(), policies=policies) as pipeline:
     response = await pipeline.run(request)
 ```
-<!-- END SNIPPET -->
+
+`\<!-- END SNIPPET -->`
+
+**Note:** you need to make sure there is
+
+\```python
+
+\```
+
+within `\<!-- SNIPPET:` & `\<!-- END SNIPPET -->` in README.MD to make the annotation valid.
 
 ## Run python_snippet_updater tool
 

tools/azure-sdk-tools/ci_tools/snippet_update/python_snippet_updater.py

@@ -7,6 +7,11 @@
 
 _LOGGER = logging.getLogger(__name__)
 
+# Uncomment the following lines to show debug info
+# _LOGGER.setLevel(logging.DEBUG)
+# console_handler = logging.StreamHandler()
+# _LOGGER.addHandler(console_handler)
+
 snippets = {}
 not_up_to_date = False
 
@@ -64,7 +69,7 @@ def get_snippet(file: str) -> None:
         if identifier in snippets.keys():
             _LOGGER.warning(f'Found duplicated snippet name "{identifier}".')
             _LOGGER.warning(file)
-        _LOGGER.debug(f"Found: {file_obj.name}.{name}")
+        _LOGGER.debug(f"Found snippet: {file_obj.name}.{name}")
         snippets[identifier] = snippet