amend change stream opts docs
amend change stream opts docs

Note that _id or the result of get_resume_token can be used as the value
of startAfter or resumeAfter

rcsanchez97/mongo-c-driver,mongodb/mongo-c-driver,mongodb/mongo-c-driver,mongodb/mongo-c-driver,jmikola/mongo-c-driver,jmikola/mongo-c-driver,rcsanchez97/mongo-c-driver,beingmeta/mongo-c-driver,jmikola/mongo-c-driver,beingmeta/mongo-c-driver,beingmeta/mongo-c-driver,mongodb/mongo-c-driver,rcsanchez97/mongo-c-driver,beingmeta/mongo-c-driver,beingmeta/mongo-c-driver,mongodb/mongo-c-driver,mongodb/mongo-c-driver,rcsanchez97/mongo-c-driver,jmikola/mongo-c-driver,jmikola/mongo-c-driver,jmikola/mongo-c-driver,jmikola/mongo-c-driver,beingmeta/mongo-c-driver,beingmeta/mongo-c-driver,mongodb/mongo-c-driver,rcsanchez97/mongo-c-driver,rcsanchez97/mongo-c-driver,beingmeta/mongo-c-driver,rcsanchez97/mongo-c-driver