Reference JSON Pointer separately

Also align the wording around JSON Pointers and Relative JSON Pointers
with the wording in the "hrefPointers" specification.

Author: handrews

jsonschema-hyperschema.xml

@@ -9,6 +9,7 @@
 <!ENTITY rfc5789 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.5789.xml">
 <!ENTITY rfc5988 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.5988.xml">
 <!ENTITY rfc6570 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.6570.xml">
+<!ENTITY rfc6906 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.6906.xml">
 <!ENTITY rfc7231 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.7231.xml">
 <!ENTITY I-D.luff-relative-json-pointer SYSTEM "https://xml2rfc.tools.ietf.org/public/rfc/bibxml3/reference.I-D.draft-luff-relative-json-pointer-00.xml">
 <!ENTITY I-D.reschke-http-jfv SYSTEM "https://xml2rfc.tools.ietf.org/public/rfc/bibxml3/reference.I-D.draft-reschke-http-jfv-06.xml">
@@ -920,10 +921,12 @@ GET /foo/
             <section title="anchorPointer" anchor="anchorPointer">
                 <t>
                     This property changes the point within the instance that is considered
-                    to be the context resource of the link.  The value of the property is a
-                    <xref target="I-D.luff-relative-json-pointer">Relative JSON Pointer</xref>,
-                    starting from the default context (the part of the instance that validated
-                    against the schema containing the LDO).
+                    to be the context resource of the link.  The value of the property MUST be a
+                    valid <xref target="RFC6906">JSON Pointer</xref>, or a valid 
+                    <xref target="I-D.luff-relative-json-pointer">Relative JSON Pointer</xref>
+                    which is evaluated relative to the position in the instance from which
+                    <xref target="href">"href"</xref> template variable resolution would
+                    normally begin.
                 </t>
                 <t>
                     While an alternate context with a known URI is best set with the
@@ -1402,6 +1405,7 @@ GET /foo/
             &rfc3986;
             <!--&rfc4287;-->
             &rfc6570;
+            &rfc6906;
             &I-D.luff-relative-json-pointer;
             &I-D.reschke-http-jfv;
             <reference anchor="json-schema">