Improves note wording

Co-authored-by: Ruben Taelman <[email protected]>

Author: Tpt

spec/index.html

@@ -4241,7 +4241,7 @@ <h3>CONSTRUCT</h3>
           (known as ground or explicit triples), and these also appear in the output RDF graph returned
           by the CONSTRUCT query form.</p>
         <p class="note">
-          Note that the construction of the result graph by "set union" does not
+          The construction of the result graph by "set union" does not
           enforce whether or not duplicated triples appear in the graph serialization.
           Implementations are allowed to produce duplicate triples or to deduplicate them.
         </p>