Booleans are able to act as schemas, so contains should not require value to be object

Author: Daniel Perrett

jsonschema-validation.xml

@@ -412,8 +412,7 @@
 
             <section title="contains">
                 <t>
-                    The value of this keyword MUST be an object.  This object MUST be
-                    a valid JSON Schema.
+                    The value of this keyword MUST be a valid JSON Schema.
                 </t>
                 <t>
                     An array instance is valid against "contains" if at least one of