replace 'trait' keyword with 'interface' in user-visible messages and code generation tools

idea/testData/quickfix/createFromUsage/createClass/delegationSpecifier/classDelegatorToSuperclass.kt

@@ -1,5 +1,5 @@
 // "Create class 'A'" "false"
-// ACTION: Create trait 'A'
+// ACTION: Create interface 'A'
 // ERROR: Unresolved reference: A
 package p
 

idea/testData/quickfix/createFromUsage/createClass/delegationSpecifier/traitDelegatorToNestedGroovySuperclass.before.Main.kt

@@ -1,4 +1,4 @@
-// "Create trait 'A'" "false"
+// "Create interface 'A'" "false"
 // ERROR: Unresolved reference: A
 class Foo: J.<caret>A {
 

idea/testData/quickfix/createFromUsage/createClass/delegationSpecifier/traitDelegatorToNestedJavaSuperclass.after.kt

@@ -1,4 +1,4 @@
-// "Create trait 'A'" "true"
+// "Create interface 'A'" "true"
 // ERROR: Unresolved reference: A
 class Foo: J.A {
 

idea/testData/quickfix/createFromUsage/createClass/delegationSpecifier/traitDelegatorToNestedJavaSuperclass.before.Main.kt

@@ -1,4 +1,4 @@
-// "Create trait 'A'" "true"
+// "Create interface 'A'" "true"
 // ERROR: Unresolved reference: A
 class Foo: J.<caret>A {
 

idea/testData/quickfix/createFromUsage/createClass/delegationSpecifier/traitDelegatorToSuperclass.kt

@@ -1,4 +1,4 @@
-// "Create trait 'A'" "true"
+// "Create interface 'A'" "true"
 package p
 
 class Foo: <caret>A {

idea/testData/quickfix/createFromUsage/createClass/delegationSpecifier/traitDelegatorToSuperclass.kt.after

@@ -1,10 +1,10 @@
-// "Create trait 'A'" "true"
+// "Create interface 'A'" "true"
 package p
 
 class Foo: A {
 
 }
 
-trait A {
+interface A {
 
 }