Migrate header/impl to expect/actual

js/src/main/kotlin/utilsImpl-js.kt

@@ -2,4 +2,4 @@ package kotlinx.html
 
 import kotlin.js.Date
 
-impl fun currentTimeMillis(): Long = Date().getTime().toLong()
+actual fun currentTimeMillis(): Long = Date().getTime().toLong()

jvm/src/main/kotlin/utilsImpl-jvm.kt

@@ -1,3 +1,3 @@
 package kotlinx.html
 
-impl fun currentTimeMillis(): Long = System.currentTimeMillis()
+actual fun currentTimeMillis(): Long = System.currentTimeMillis()

shared/src/main/kotlin/Event.kt

@@ -1,7 +1,7 @@
 package org.w3c.dom.events
 
 @Suppress("HEADER_WITHOUT_IMPLEMENTATION", "NO_ACTUAL_FOR_EXPECT")
-header interface Event {
+expect interface Event {
     fun stopPropagation()
     fun preventDefault()
 

shared/src/main/kotlin/util.kt

@@ -14,4 +14,4 @@ val Tag.br : Unit
         consumer.onTagEnd(tag)
     }
 
-header fun currentTimeMillis(): Long
+expect fun currentTimeMillis(): Long