Clarify that plain name fragments are neither canonical or non-canonical (#1192)

* Clarify that plain name fragments are neither canonical or non-canonical
Attempt to resolve #937
Add note and cref in appendix A clarifying that we intended to define a URI phrasing which would avoid the requirement to allow for location shadowing in implementations, as this is tricky. Clarifying that plain name fragments should always be supported, and that they only can work in relation to the base URI of the Schema Resource. Otherwise there could be duplicate plain name fragments and addressing wouldn't work.

Author: Relequestual

jsonschema-core.xml

@@ -50,7 +50,7 @@
             </address>
         </author>
 
-        <date year="2021"/>
+        <date year="2022"/>
         <workgroup>Internet Engineering Task Force</workgroup>
         <keyword>JSON</keyword>
         <keyword>Schema</keyword>
@@ -1824,10 +1824,10 @@
                         reference target, is preferable.
                     </t>
                     <t>
-                        An implementation MAY choose not to support addressing schemas
-                        by non-canonical URIs. As such, it is RECOMMENDED that schema authors only
-                        use canonical URIs, as using non-canonical URIs may reduce
-                        schema interoperability.
+                        An implementation MAY choose not to support addressing schema resources
+                        (and their subschemas) by non-canonical URIs.
+                        As such, it is RECOMMENDED that schema authors only use canonical URIs,
+                        as using non-canonical URIs may reduce schema interoperability.
                         <cref>
                             This is to avoid requiring implementations to keep track of a whole
                             stack of possible base URIs and JSON Pointer fragments for each,
@@ -1836,6 +1836,11 @@
                             no point in forbidding it, while others have argued that it complicates
                             schema identification and should be forbidden.  Feedback on this
                             topic is encouraged.
+                            After some discussion, we feel that we need to remove the use of
+                            "canonical" in favour of talking about JSON Pointers which reference
+                            across schema resource boundaries as undefined or even forbidden behavior
+                            (https://github.com/json-schema-org/json-schema-spec/issues/937,
+                            https://github.com/json-schema-org/json-schema-spec/issues/1183)
                         </cref>
                     </t>
                     <t>
@@ -3390,6 +3395,18 @@ https://example.com/schemas/common#/$defs/count/minimum
                     </t>
                 </list>
             </t>
+            <t>
+                Note: The fragment part of the URI does not make it canonical or non-canonical,
+                rather, the base URI used (as part of the full URI with any fragment) is what
+                determines the canonical nature of the resulting full URI.
+                <cref>
+                    Multiple "canonical" URIs? We Acknowledge this is potentially confusing, and
+                    direct you to read the CREF located in the
+                    <xref target="embedded">JSON Pointer fragments and embedded schema resources</xref>
+                    section for futher comments.
+                </cref>
+            </t>
+
         </section>
 
         <section title="Manipulating schema documents and references">