Add HN related lemma's

Author: lizmat

S99-glossary.pod

@@ -329,6 +329,14 @@ system.
 A data type, conveniently available in variables starting with the percent sign
 C<%> and provided by type C<Hash>.
 
+=head2 HN
+
+Hacker news as seen on L<https://news.ycombinator.com>.
+
+=head2 HN'ed
+
+Being mentioned on Hacker news (L<https://news.ycombinator.com>).
+
 =head2 HPMoR
 
 Harry Potter and the Methods of Rationality. An inexplicably good Harry Potter