burst tagger: Fixed off-by-one in get_tags_in_range() usage

I've observed missing "tx_sob" tags in case where d_tag_name is
associated with the last sample provided to work().

This is caused by the upper-bound provided to get_tags_in_range() being
1 less than it should be.

Per the documentation of get_tags_in_range() (as of v3.7.7.1), the
abs_end value is exclusive:
  "Given a [start,end), returns a vector of all tags in the range
   with a given key."

Therefore, the upper limit should be:
    nread + nouput_items
not
    nread + noutput_items - 1

Example:
    let nread = 100
    let noutput_items = 100

    We want tags within:
        [100, 199] = [nread, n_read + n_output_items - 1]

    Represented with an exclusive upper bound, as required by
    get_tags_in_range():
        [100, 200) = [nread, n_read + nouput_items)

lib/burst_tagger_impl.cc

@@ -73,8 +73,7 @@ burst_tagger_impl::work(int noutput_items,
 		std::vector<gr::tag_t> tags;
 		const uint64_t nread = nitems_read(0);
 
-		get_tags_in_range(tags, 0, nread, nread + noutput_items - 1,
-			d_tag_name);
+		get_tags_in_range(tags, 0, nread, nread + noutput_items, d_tag_name);
 		std::sort(tags.begin(), tags.end(), tag_t::offset_compare);
 
 		// copy until the first tag