Update spec/index.html

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

Author: pchampin

spec/index.html

@@ -108,7 +108,7 @@
     Finally, to ease the transition from RDF 1.1 to RDF 1.2,
     this specification introduces a mechanism for
     <a href="#section-version-announcement">explicitly conveying</a>
-    which version of RDF is used by a given piece of data.
+    the version of RDF that is used by a given piece of data.
   </p>
 
   <p>This specification introduces key concepts and terminology for RDF 1.2, and subsequently discusses