Add "anchorPointer" to the meta-schema.

The "anyOf" is an attempt to convey some information about
the Relative JSON Pointer even though we don't have a format
for it (yet?)

It is an "anyOf" rather than a "oneOf" because if an
implementation does not support "format", a "oneOf" would
likely fail incorrectly.

Author: handrews

hyper-schema.json

@@ -34,6 +34,14 @@
                     "type": "string",
                     "format": "uri-reference"
                 },
+                "anchorPointer": {
+                    "description": "a Relative JSON Pointer adjusting the link context within the instance",
+                    "type": "string",
+                    "anyOf": [
+                        { "format": "json-pointer" },
+                        { "pattern": "^[0-9]" }
+                    ]
+                },
                 "title": {
                     "description": "a title for the link",
                     "type": "string"