Update ECMA-262 link

According to the main ECMA-262 page, the link needs an "index.html" suffix.
There's no guarantee that linking to the raw "11.0/" directory will lead to
the correct place, even if it does. This updates to the correct rell-known
link. Not all sites necessarily support a default page for an empty
path suffix.

Ref: https://www.ecma-international.org/publications/standards/Ecma-262.htm

Author: ssilverman

jsonschema-core.xml

@@ -3296,7 +3296,7 @@ https://example.com/schemas/common#/$defs/count/minimum
             &RFC8259;
             &ldp;
             <reference anchor="ecma262"
-            target="https://www.ecma-international.org/ecma-262/11.0">
+            target="https://www.ecma-international.org/ecma-262/11.0/index.html">
                 <front>
                     <title>ECMA-262, 11th edition specification</title>
                     <author/>