[java] UselessPureMethodCall: add IntStream/LongStream/DoubleStream to known-pure methods - fix pmd#6517

Add primitive stream types (IntStream, LongStream, DoubleStream) to
KNOWN_PURE_METHODS so that any discarded non-void method call on these
types is reported, not just peek.

Previously only java.util.stream.Stream was listed; the three primitive
stream variants were missing, causing a false negative for peek and all
other non-void methods on those types.

Author: leemeii

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/internal/JavaRuleUtil.java

@@ -60,6 +60,9 @@ public final class JavaRuleUtil {
         // actually not all of them, probs only stream of some type
         // arg which doesn't implement Closeable...
         "java.util.stream.Stream#_(_*)",
+        "java.util.stream.IntStream#_(_*)",
+        "java.util.stream.LongStream#_(_*)",
+        "java.util.stream.DoubleStream#_(_*)",
         "java.util.Collection#contains(_)",
         "java.util.Collection#size()",
         "java.util.List#get(int)",

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/errorprone/xml/UselessPureMethodCall.xml

@@ -455,4 +455,31 @@ class Tester {
         }
         ]]></code>
     </test-code>
+
+    <test-code>
+        <description>[java] UselessPureMethodCall false negative for primitive stream peek #6517</description>
+        <expected-problems>4</expected-problems>
+        <expected-linenumbers>8,11,14,17</expected-linenumbers>
+        <code><![CDATA[
+import java.util.stream.Stream;
+import java.util.stream.IntStream;
+import java.util.stream.LongStream;
+import java.util.stream.DoubleStream;
+
+public class a {
+    public void tp() {
+        Stream.of("A", "B").peek(System.out::println);
+    }
+    public void fn1() {
+        IntStream.of(1, 2).peek(System.out::println);
+    }
+    public void fn2() {
+        LongStream.of(1, 2).peek(System.out::println);
+    }
+    public void fn3() {
+        DoubleStream.of(1.0, 2.0).peek(System.out::println);
+    }
+}
+        ]]></code>
+    </test-code>
 </test-data>