mention sink means void elsewhere

Author: TimToady

S99-glossary.pod

@@ -8,8 +8,8 @@ Synopsis 99: Glossary
 
     Created: 26 June 2013
 
-    Last Modified: 18 Aug 2014
-    Version: 7
+    Last Modified: 26 Feb 2015
+    Version: 8
 
 This document tries to define many of the terms used within the Perl 6
 community.  It does not have an Apocalypse or Exegesis predecessor.  It
@@ -1793,7 +1793,8 @@ or even C<postcircumfix> L<expression|/Expression>s starting with such a variabl
 
 =head2 sink context
 
-L<Context|/context> of an expression whose value is ignored.
+L<Context|/context> of an expression whose value is ignored.  Often called "void" context
+in other languages.
 
 =head2 sixplanet