always pass bookmark name through to domainmapper

the rtf doc has three bookmark starts but only two matching
bookmark ends.

The tokenizer has three starts 0, 1, 2, but 0 is missing an end. Without the
end of 0, the mapper never inserts an entry for it, so later inserts the start
of rtftok index 1 as mapper index 0, and passing the end for a bare "1" cannot
be found by index. If we pass the name then it finds it by name as mapper index
0 and all is well.

Change-Id: I344db84e4f1c7d55fca59cdfe692080c7d0b8033
(cherry picked from commit 2b54caceab9d975bffa7e24bf732cb877b16632f)
Reviewed-on: https://gerrit.libreoffice.org/13133
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Miklos Vajna <vmiklos@collabora.co.uk>