Add claim delimiter configuration example in OAuth2 Resource Server JWT documentation

Expected Behavior

An example for configuring the claim delimiter is listed in the Extracting Authorities section of the OAuth2 Resource Server JWT documentation.

Current Behavior

The JwtGrantedAuthoritiesConverter has 3 available methods for configuration. But only 2, namely the configuration of the authorities claim and the authorities prefix, are outlined in the documentation.

Context

About a year ago I opened a PR that added the possibility to configure the claim delimiter. Now I would like to outline this configuration option in the Spring documentation. The configuration example I want to add would be the same as in the test of the method, with the relevant lines being:

JwtGrantedAuthoritiesConverter jwtGrantedAuthoritiesConverter = new JwtGrantedAuthoritiesConverter();
jwtGrantedAuthoritiesConverter.setAuthoritiesClaimDelimiter(",");

With this issue I would like to discuss if it is ok to outline this configuration in the documentation.