remove support for 'trait' keyword

compiler/testData/codegen/box/classes/kt6136.kt

@@ -1,4 +1,4 @@
-trait Id<T> {
+interface Id<T> {
     val id: T
 }
 

compiler/testData/codegen/box/defaultArguments/function/kt5232.kt

@@ -1,4 +1,4 @@
-trait A {
+interface A {
     fun visit(a:String, b:String="") : String = b + a
 }
 

compiler/testData/codegen/box/increment/postfixIncrementOnClass.kt

@@ -1,4 +1,4 @@
-trait Base
+interface Base
 class Derived: Base
 class Another: Base
 fun Base.inc(): Derived { return Derived() }

compiler/testData/codegen/box/increment/prefixIncrementOnClass.kt

@@ -1,4 +1,4 @@
-trait Base
+interface Base
 class Derived: Base
 class Another: Base
 fun Base.inc(): Derived { return Derived() }

compiler/testData/codegen/boxWithJava/interfaces/abstractClassInheritsFromInterface/KC.kt

@@ -1,6 +1,6 @@
 // KT-3407 Implementing (in Java) an abstract Kotlin class that implements a trait does not respect trait method definition
 
-trait T {
+interface  T {
     fun foo() = "OK"
 }
 

compiler/testData/codegen/java8/boxWithJava/defaultMethodCallFromTrait/defaultCall.kt

@@ -1,4 +1,4 @@
-trait KTrait : Simple {
+interface KTrait : Simple {
     fun bar(): String {
         return test("O") + Simple.testStatic("O")
     }

compiler/testData/codegen/java8/boxWithJava/defaultMethodOverride/override.kt

@@ -1,4 +1,4 @@
-trait KTrait: Simple {
+interface KTrait: Simple {
     override fun test(s: String): String {
         return s + "K"
     }

compiler/testData/codegen/java8/boxWithJava/inheritKotlin/defaultCall.kt

@@ -1,4 +1,4 @@
-trait KTrait {
+interface KTrait {
     fun test(): String {
         return "base";
     }

compiler/testData/codegen/java8/boxWithJava/invokeDefaultViaSuper/tesk.kt

@@ -1,4 +1,4 @@
-trait KTrait : Test {
+interface KTrait : Test {
 
 }
 

compiler/testData/diagnostics/tests/DeprecatedTraitKeyword.kt

@@ -1,2 +0,0 @@
-<!DEPRECATED_TRAIT_KEYWORD!>trait<!> A {
-}

compiler/testData/diagnostics/tests/DeprecatedTraitKeyword.txt

@@ -1,7 +0,0 @@
-package
-
-public interface A {
-    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
-}

compiler/testData/loadJava/compiledKotlin/annotations/types/SupertypesAndBounds.kt

@@ -2,6 +2,6 @@ package test
 
 annotation class A
 
-trait Foo<T : @A Number> : @A CharSequence {
+interface Foo<T : @A Number> : @A CharSequence {
     fun <E, F : @A E> bar()
 }

compiler/testData/psi/annotation/targeted/onFile/fileAnnotationInWrongPlace.kt

@@ -10,7 +10,7 @@ fun func() {}
 class C
 
 @file:
-trait T
+interface T
 
 @file:[]
-trait T
+interface T

compiler/testData/psi/annotation/targeted/onFile/fileAnnotationInWrongPlace.txt

@@ -85,7 +85,7 @@ JetFile: fileAnnotationInWrongPlace.kt
         PsiElement(IDENTIFIER)('file')
         PsiElement(COLON)(':')
     PsiWhiteSpace('\n')
-    PsiElement(trait)('trait')
+    PsiElement(interface)('interface')
     PsiWhiteSpace(' ')
     PsiElement(IDENTIFIER)('T')
   PsiWhiteSpace('\n\n')
@@ -101,6 +101,6 @@ JetFile: fileAnnotationInWrongPlace.kt
           <empty list>
         PsiElement(RBRACKET)(']')
     PsiWhiteSpace('\n')
-    PsiElement(trait)('trait')
+    PsiElement(interface)('interface')
     PsiWhiteSpace(' ')
     PsiElement(IDENTIFIER)('T')

compiler/testData/renderer/TraitWithConstructor.kt

@@ -1,10 +1,10 @@
-trait A1() {
+interface  A1() {
     constructor(x: Int = "", y: Int) : this() {
         x + y
     }
 }
 
-trait A2 private constructor(private val prop: Int) {
+interface  A2 private constructor(private val prop: Int) {
     constructor(x: Int = "", y: Int) : this(x * y) {
         x + y
     }