add documentation for the redirect rewrite rule

securing_apps/topics/oidc/java/java-adapter-config.adoc

@@ -35,7 +35,10 @@ This is what one might look like:
    "client-key-password" : "geheim",
    "token-minimum-time-to-live" : 10,
    "min-time-between-jwks-requests" : 10,
-   "public-key-cache-ttl": 86400
+   "public-key-cache-ttl": 86400,
+   "redirect-rewrite-rules" : {
+   "^/wsmaster/api/(.*)$" : "/api/$1"
+   }
 }
 ----
 
@@ -237,3 +240,7 @@ ignore-oauth-query-parameter::
   Defaults to `false`, if set to `true` will turn off processing of the `access_token`
   query parameter for bearer token processing.  Users will not be able to authenticate
   if they only pass in an `access_token`
+
+redirect-rewrite-rules::
+  If needed, specify the Redirect URI rewrite rule. This is an object notation where the key is the regular expression to which the Redirect URI is to be matched and the value is the replacement String.
+  `$` character can be used for backreferences in the replacement String.