Adds «property» refs #728

Author: JJ

doc/Language/glossary.pod6

@@ -795,6 +795,10 @@ X<|POD>
 B<P>lain B<O>l' B<D>ocumentation, a documentation format understood by Perl
 6. See L<S26|https://design.perl6.org/S26.html> for details.
 
+=head1 property
+
+In this context, it either refers to an L<object property|https://docs.perl6.org/language/objects#index-entry-Property>, which is the value of an instance variable, or an L<Unicode property|https://docs.perl6.org/language/regexes#Unicode_Properties> which are codepoint features that allow programs to identify what kind of entity they represent, that is, if they are a letter, or a number, or something completely different like a control character.
+
 =head1 Pull Request
 X<|Pull Request>