improve begin_translation docstring (Azure#20401)

Author: kristapratico

sdk/translation/azure-ai-translation-document/azure/ai/translation/document/_client.py

@@ -113,10 +113,13 @@ def begin_translation(
         self, *args, **kwargs
     ):  # pylint: disable=client-method-missing-type-annotations
         """Begin translating the document(s) in your source container to your target container
-        in the given language. To perform a single translation from source to target, pass the `source_url`,
-        `target_url`, and `target_language_code` parameters including any optional keyword arguments.
-        To pass multiple inputs for translation, pass the `inputs` parameter as a list of
-        :class:`~azure.ai.translation.document.DocumentTranslationInput`.
+        in the given language. There are two ways to call this method:
+
+        1) To perform translation on documents from a single source container to a single target container, pass the
+        `source_url`, `target_url`, and `target_language_code` parameters including any optional keyword arguments.
+
+        2) To pass multiple inputs for translation (multiple sources or targets), pass the `inputs` parameter
+        as a list of :class:`~azure.ai.translation.document.DocumentTranslationInput`.
 
         For supported languages and document formats, see the service documentation:
         https://docs.microsoft.com/azure/cognitive-services/translator/document-translation/overview

sdk/translation/azure-ai-translation-document/azure/ai/translation/document/aio/_client_async.py

@@ -122,10 +122,13 @@ async def begin_translation(
         self, *args, **kwargs
     ):  # pylint: disable=client-method-missing-type-annotations
         """Begin translating the document(s) in your source container to your target container
-        in the given language. To perform a single translation from source to target, pass the `source_url`,
-        `target_url`, and `target_language_code` parameters including any optional keyword arguments.
-        To pass multiple inputs for translation, pass the `inputs` parameter as a list of
-        :class:`~azure.ai.translation.document.DocumentTranslationInput`.
+        in the given language. There are two ways to call this method:
+
+        1) To perform translation on documents from a single source container to a single target container, pass the
+        `source_url`, `target_url`, and `target_language_code` parameters including any optional keyword arguments.
+
+        2) To pass multiple inputs for translation (multiple sources or targets), pass the `inputs` parameter
+        as a list of :class:`~azure.ai.translation.document.DocumentTranslationInput`.
 
         For supported languages and document formats, see the service documentation:
         https://docs.microsoft.com/azure/cognitive-services/translator/document-translation/overview