status: report number of active worker threads in status output

This is especially useful when dynamic load management allocates more
worker threads than active tasks, so the extra threads are effectively
invisible.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>

src/bees-context.cc

@@ -99,7 +99,7 @@ BeesContext::dump_status()
 		ofs << "RATES:\n";
 		ofs << "\t" << avg_rates << "\n";
 
-		ofs << "THREADS (work queue " << TaskMaster::get_queue_count() << " tasks):\n";
+		ofs << "THREADS (work queue " << TaskMaster::get_queue_count() << " tasks, " << TaskMaster::get_thread_count() << " workers):\n";
 		for (auto t : BeesNote::get_status()) {
 			ofs << "\ttid " << t.first << ": " << t.second << "\n";
 		}