Adds sigilless variables refs #622

Author: JJ

doc/Language/glossary.pod6

@@ -1030,6 +1030,8 @@ such a variable.
 =head1 Sigilless Variable
 X<|Sigilless Variable>
 
+L<Sigilless variables|/language/variables#index-entry-\_(sigilless_variables)> are actually aliases to the value it is assigned to them, since they are not containers. Once you assign a sigilless variable (using the escape C<\>), its value cannot be changed.
+
 =head1 Spesh
 X<|Spesh>