Update schema_definition-array.yaml

Author: cmungall

tests/input/examples/schema_definition-array.yaml

@@ -66,6 +66,8 @@ classes:
           ucum_code: s
       length:  # must be defined by outer container when it cannot be inferred
         range: integer
+        implements:
+          - linkml:length
       values:
         range: float
         multivalued: true