Add format split to the validation changelog

Author: Relequestual

jsonschema-validation.xml

@@ -1426,7 +1426,7 @@
                             <t>Correct email format RFC reference to 5321 instead of 5322</t>
                             <t>Clarified the set and meaning of "contentEncoding" values</t>
                             <t>Reference ECMA-262, 11th edition for regular expression support</t>
-                            <t></t>
+                            <t>Split "format" into an annotation only vocabulary and an assertion vocabulary</t>
                             <t></t>
                             <t></t>
                             <t></t>