fix wrong document about "jws-algorithms"

```
$ git grep jws-algorithm
docs/modules/ROOT/pages/reactive/oauth2/resource-server/jwt.adoc:          jws-algorithm: RS512
docs/modules/ROOT/pages/servlet/oauth2/resource-server/jwt.adoc:          jws-algorithm: RS512
```

It's `jws-algorithms`,  miss the trailing `s`.