remove support for 'trait' keyword

idea/testData/quickfix/deprecatedSymbolUsage/methodToProperty.kt

@@ -1,6 +1,6 @@
 // "Replace with 'x'" "true"
 
-trait X {
+interface X {
     @Deprecated("", ReplaceWith("x"))
     fun getX(): String
 

idea/testData/quickfix/deprecatedSymbolUsage/methodToProperty.kt.after

@@ -1,6 +1,6 @@
 // "Replace with 'x'" "true"
 
-trait X {
+interface X {
     @Deprecated("", ReplaceWith("x"))
     fun getX(): String
 

idea/testData/quickfix/deprecatedSymbolUsage/propertyToMethod.kt

@@ -1,6 +1,6 @@
 // "Replace with 'getX()'" "true"
 
-trait X {
+interface X {
     @Deprecated("", ReplaceWith("getX()"))
     val x: String
 

idea/testData/quickfix/deprecatedSymbolUsage/propertyToMethod.kt.after

@@ -1,6 +1,6 @@
 // "Replace with 'getX()'" "true"
 
-trait X {
+interface X {
     @Deprecated("", ReplaceWith("getX()"))
     val x: String
 

idea/testData/quickfix/migration/traitToInterface/traitToInterface.kt

@@ -1,5 +0,0 @@
-// "Replace 'trait' with 'interface'" "true"
-
-<caret>trait Foo {
-
-}

idea/testData/quickfix/migration/traitToInterface/traitToInterface.kt.after

@@ -1,5 +0,0 @@
-// "Replace 'trait' with 'interface'" "true"
-
-<caret>interface Foo {
-
-}

idea/testData/quickfix/supertypeInitialization/genericClass.kt

@@ -1,5 +1,5 @@
 // "Add constructor parameters from Base(T, String, Base<T, String>?)" "true"
-trait I
+interface I
 
 open class Base<T1, T2>(p1: T1, p2: T2, p3: Base<T1, T2>?)
 

idea/testData/quickfix/supertypeInitialization/genericClass.kt.after

@@ -1,5 +1,5 @@
 // "Add constructor parameters from Base(T, String, Base<T, String>?)" "true"
-trait I
+interface I
 
 open class Base<T1, T2>(p1: T1, p2: T2, p3: Base<T1, T2>?)