fixed 'assertation' typo

Author: gregsdennis

jsonschema-validation.xml

@@ -547,7 +547,7 @@
                     In addition to the Format-Annotation vocabulary, a secondary vocabulary is available
                     for custom meta-schemas that defines "format" as an assertion. The URI for the
                     Format-Assertion vocabulary, is:
-                    <https://json-schema.org/draft/2020-11/vocab/format-assertation>.
+                    <https://json-schema.org/draft/2020-11/vocab/format-assertion>.
                 </t>
                 <t>
                     The current URI for the corresponding meta-schema is: