[core] RuleSetFactory - recognize rule reference for same ruleset

There are two variants, how a renamed rule can be expressed in the
ruleset via a deprecated rule reference: referencing just the
new rule name or referencing the ruleset+new rule name. The latter
case was not covered yet, it was not detected, that the rule ref
references are rule in the same ruleset.

Fixes #2096

pmd-dist/src/test/java/net/sourceforge/pmd/it/AllRulesIT.java

@@ -40,6 +40,7 @@ public class AllRulesIT extends AbstractBinaryDistributionTest {
         result.assertNoError("Exception applying rule");
         result.assertNoError("Ruleset not found");
         result.assertNoError("Use of deprecated attribute");
+        result.assertNoError("instead of the deprecated"); // rule deprecations
         result.assertNoErrorInReport("Error while processing");
         result.assertNoErrorInReport("Error while parsing");