Apply suggestions from code review

Co-authored-by: Thomas Tanon 

Author: rubensworks

spec/index.html

@@ -372,8 +372,8 @@ Introduction
 	    <h3>Version Announcementh3>
 	    <p>To indicate that RDF 1.2 features are used in the SPARQL results,
         such as <a data-cite="RDF12-CONCEPTS#dfn-base-direction">initial text directiona> or <a data-cite="RDF12-CONCEPTS#dfn-triple-term">triple termsa>,
-	    the optional `version` <a href="#media-type">Media Type parametera> can be set to `1.2`.
-        Alternatively, the <a href="#select-version">`"version"` membera> can be used to specify this version.p>
+	    the optional `version` <a href="#media-type">Media Type parametera> MAY be set to `1.2`.
+        Alternatively, the <a href="#select-version">`"version"` membera> MAY be used to specify this version.p>
         <p>When providing content over HTTP, servers can announce the version
         using the optional `version` <a href="#media-type">Media Type parametera>:p>
 
@@ -398,7 +398,7 @@ Version Announcement
 
         <p class="note">Version numbers other than "1.2" are not defined by
         this specification.
-        Processors may treat this as an error or warning.p>
+        Processors MAY treat this as an error or warning.p>
 	  section>
     section>
     <section id="json-result-object">
@@ -479,7 +479,7 @@ "link"
         <section id="select-version">
           <h4>"version"h4>
           <p>The optional <code>"version"code> string member, along with an optional `version` <a href="#media-type">Media Type parametera>,
-          can be used to announce that RDF 1.2 functionalities are used in the results.p>
+          MAY be used to announce that RDF 1.2 functionalities are used in the results.p>
           <pre class="box json">"version" : "1.2" pre>
         section>
       section>