[translation] add keywords to assist in searching for the package in pypi (Azure#22882)

* add keywords to assist in searching for the package in pypi

* add kws that describe what the package does

Author: kristapratico

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

@@ -31,6 +31,7 @@
     long_description=readme + '\n\n' + changelog,
     long_description_content_type='text/markdown',
     url='https://github.com/Azure/azure-sdk-for-python',
+    keywords="azure, cognitive services, document translation, document translator, translator, translate, translation",
     author='Microsoft Corporation',
     author_email='azpysdkhelp@microsoft.com',
     license='MIT License',