docs: add docs for bson_iter_binary(3)
docs: add docs for bson_iter_binary(3)

jqk6/libbson,Machyne/libbson,rcsanchez97/libbson,Convey-Compliance/libbson,derickr/libbson,rayyang2000/libbson,ksuarz/libbson,Convey-Compliance/libbson,bjori/libbson,ajdavis/libbson,jqk6/libbson,mapr/libbson,alexeyvo/libbson,rcsanchez97/libbson,ajdavis/libbson,rayyang2000/libbson,remicollet/libbson,alexeyvo/libbson,mongodbinc-interns/libbson,paulmelnikow/libbson,rayyang2000/libbson,mongodb/libbson,mongodb/libbson,jqk6/libbson,mongodb/libbson,mongodbinc-interns/libbson,derickr/libbson,ksuarz/libbson,mongodbinc-interns/libbson,4Second2None/libbson_tmp,Machyne/libbson,4Second2None/libbson_tmp,mongodbinc-interns/libbson,bjori/libbson,derickr/libbson,4Second2None/libbson_tmp,bjori/libbson,mapr/libbson,paulmelnikow/libbson,paulmelnikow/libbson,rcsanchez97/libbson,ajdavis/libbson,Machyne/libbson,4Second2None/libbson_tmp,mapr/libbson,paulmelnikow/libbson,ksuarz/libbson,remicollet/libbson,remicollet/libbson,alexeyvo/libbson,paulmelnikow/libbson,remicollet/libbson,rayyang2000/libbson,derickr/libbson,jqk6/libbson,Machyne/libbson,Convey-Compliance/libbson