Fix dead link for definitely not compliant enumNames property (rjsf-team#1752)

* Fix dead link for definitely not compliant `enumNames` property

* Update single.md

Co-authored-by: Ashwin Ramaswami <[email protected]>

Author: jnachtigall

docs/usage/single.md

@@ -57,7 +57,7 @@ render((
 
 ### Custom labels for `enum` fields
 
-This library supports the [`enumNames`](https://github.com/json-schema/json-schema/wiki/enumNames-%28v5-proposal%29) property for `enum` fields, which allows defining custom labels for each option of an `enum`:
+This library supports a custom [`enumNames`](https://github.com/rjsf-team/react-jsonschema-form/issues/57) property for `enum` fields, which, however is not JSON-Schema compliant (see below for a compliant approach). The `enumNames` property allows defining custom labels for each option of an `enum`:
 
 ```jsx
 const schema = {
@@ -140,4 +140,4 @@ const schema = {
 render((
   <Form schema={schema} />
 ), document.getElementById("app"));
-```
+```