Add example of 1-ZST and not to the glossary

Author: gnzlbg

reference/src/glossary.md

@@ -77,8 +77,10 @@ niche.
 
 Types with zero size are called zero-sized types, which is abbreviated as "ZST".
 This document also uses the "1-ZST" abbreviation, which stands for "one-aligned
-zero-sized type", to refer to zero-sized types with an alignment requirement of
-1.
+zero-sized type", to refer to zero-sized types with an alignment requirement of 1. 
+
+For example, `()` is a "1-ZST" but `[u16; 0]` is not because it has an alignment
+requirement of two.
 
 ### TODO