Exclude .kt files from useless parameter query

Author: tamasvajk

java/ql/lib/semmle/code/java/deadcode/DeadCode.qll

@@ -274,7 +274,7 @@ class DeadMethod extends Callable {
 
 class RootdefCallable extends Callable {
   RootdefCallable() {
-    this.fromSource() and
+    this.getFile().isJavaSourceFile() and
     not this.(Method).overridesOrInstantiates(_)
   }
 

java/ql/test/kotlin/query-tests/UselessParameter/UselessParameter.expected

@@ -1,3 +0,0 @@
-| Test.kt:11:8:11:18 | a | The parameter 'a' is never used. |
-| Test.kt:19:5:19:5 | <this> | The parameter '<this>' is never used. |
-| Test.kt:24:9:24:14 | a | The parameter 'a' is never used. |