improve error info when no sample code found (#42742)

* test=document_fix

* exit 1 if no sample code found since api must have sample code;test=document_fix

* test normal input;test=document_fix

* delete test code;test=document_fix

tools/sampcd_processor.py

@@ -339,8 +339,10 @@ def sampcd_extract_to_file(srccom, name, htype="def", hname=""):
 Please use '.. code-block:: python' to format the sample code.""")
                 return []
         else:
-            logger.warning("Error: No sample code!")
-            return []
+            logger.error(
+                "Error: No sample code found! Please check if the API comment contais string 'Examples:' correctly"
+            )
+            exit(1)
 
     sample_code_filenames = []
     for y, cb in enumerate(codeblocks):