Renamed *.jet to *.kt in test data of JetPsiCheckerTest.

idea/testData/checker/Override.kt

@@ -0,0 +1,36 @@
+package override
+
+    trait MyTrait {
+        fun foo()
+    }
+
+    abstract class MyAbstractClass {
+        abstract fun bar()
+    }
+
+    open class MyClass : MyTrait, MyAbstractClass() {
+        override fun foo() {}
+        override fun bar() {}
+    }
+
+    class MyChildClass : MyClass() {}
+
+    class <error>MyIllegalClass</error> : MyTrait, MyAbstractClass() {}
+
+    class <error>MyIllegalClass2</error> : MyTrait, MyAbstractClass() {
+        override fun foo() {}
+    }
+
+    class <error>MyIllegalClass3</error> : MyTrait, MyAbstractClass() {
+        override fun bar() {}
+    }
+
+    class <error>MyIllegalClass4</error> : MyTrait, MyAbstractClass() {
+        <error>fun foo()</error> {}
+        <error>override</error> fun other() {}
+    }
+
+    class MyChildClass1 : MyClass() {
+        <error>fun foo()</error> {}
+        override fun bar() {}
+    }