Tokens, along with their syntactic information, in the input
document. Populated if the user enables [AnnotateTextRequest.F
eatures.extract_syntax][google.cloud.language.v1.AnnotateText
Request.Features.extract_syntax].
The overall sentiment for the document. Populated if the user
enables [AnnotateTextRequest.Features.extract_document_senti
ment][google.cloud.language.v1.AnnotateTextRequest.Features.ex
tract_document_sentiment].