Fix type for rest-client-access-token-response-client.adoc

In line 260, there is the mention of "=== Customizing the `WebClient`" while it should be "=== Customizing the `RestClient`"

Signed-off-by: patpatpat123 <43899031+patpatpat123@users.noreply.github.com>

docs/modules/ROOT/partials/servlet/oauth2/client/rest-client-access-token-response-client.adoc

@@ -257,7 +257,7 @@ accessTokenResponseClient.setParametersCustomizer { parameters ->
 `{class-name}` provides hooks for customizing response parameters and error handling of the OAuth 2.0 Access Token Response.
 
 [#oauth2-client-{section-id}-access-token-response-rest-client]
-=== Customizing the `WebClient`
+=== Customizing the `RestClient`
 
 You can customize the Token Response by providing a pre-configured `RestClient` to `setRestClient()`.
 The default `RestClient` is configured as follows: