Name finding interface which processes an entire document allowing the name finder to use context
from the entire document.
This interface has been added as part of a work in progress and might change without notice.
Returns tokens span for the specified document of sentences and their tokens.
Span start and end indices are relative to the sentence they are in.
For example, a span identifying a name consisting of the first and second word
of the second sentence would be 0..2 and be referenced as spans.
document - An array of tokens for each sentence of a document.
The token spans for each sentence of the specified document.