docs: add docs for bson_reader_destroy(3)
docs: add docs for bson_reader_destroy(3)

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