Improves note wording

Co-authored-by: Ted Thibodeau Jr <[email protected]>

Author: Tpt

spec/index.html

@@ -4242,7 +4242,7 @@ <h3>CONSTRUCT</h3>
           by the CONSTRUCT query form.</p>
         <p class="note">
           Note that the construction of the result graph by "set union" does not
-          enforce anything on the appearance or not of duplicated triples in the graph serialization.
+          enforce whether or not duplicated triples appear in the graph serialization.
           Implementations are allowed to produce duplicate triples or to deduplicate them.
         </p>
         <div class="exampleGroup">