Move predicate_label examples to predicate_id in sssom_schema.yaml

Fixes #369.

The examples for the predicate_id slot where in the wrong slot (predicate_label), here we move them to be correct.

I have also added a single example for the predicate_label slot.

src/sssom_schema/schema/sssom_schema.yaml

@@ -183,19 +183,7 @@ slots:
     range: EntityReference
     required: true
     slot_uri: owl:annotatedProperty
-    examples:
-      - value: skos:exactMatch
-  predicate_modifier:
-    description: A modifier for negating the prediate. See https://github.com/mapping-commons/sssom/issues/40 for discussion
-    range: predicate_modifier_enum
-    see_also:
-      - https://github.com/mapping-commons/sssom/issues/107
-    examples:
-      - value: Not
-        description: Negates the predicate, see documentation of predicate_modifier_enum
-  predicate_label:
-    description: The label of the predicate/relation of the mapping
-    range: string
+
     examples:
       - value: owl:sameAs
         description: The subject and the object are instances (owl individuals), and the two instances are the same.
@@ -221,6 +209,20 @@ slots:
         description: Two terms are related in some way. The meaning is frequently consistent across a single set of mappings. Note this property is often overloaded even where the terms are of a different nature (e.g. interpro2go)
       - value: rdfs:seeAlso
         description: The subject and the object are associated in some unspecified way. The object IRI often resolves to a resource on the web that provides additional information.
+  predicate_modifier:
+    description: A modifier for negating the prediate. See https://github.com/mapping-commons/sssom/issues/40 for discussion
+    range: predicate_modifier_enum
+    see_also:
+      - https://github.com/mapping-commons/sssom/issues/107
+    examples:
+      - value: Not
+        description: Negates the predicate, see documentation of predicate_modifier_enum
+  predicate_label:
+    description: The label of the predicate/relation of the mapping
+    range: string
+    examples:
+      - value: has cross-reference
+        description: The label of the oboInOwl:hasDbXref property to represent cross-references.
   predicate_type:
     description: The type of entity that is being mapped.
     range: entity_type_enum