Replace deprecated methods in FormatHtmlUtil.

idea/tests/org/jetbrains/kotlin/idea/highlighter/FormatHtmlUtil.kt

@@ -35,6 +35,6 @@ private fun formatHtml(html: String): String {
     }
     message = message.replace("<br/>", "<br/>\n").replace("&nbsp;", " ")
     message = message.replace("&lt;", "<`").replace("&gt;", ">")
-    message = message.split("(\r|\n|\r\n)+").map { s -> s.trimTrailing() }.filter { s -> !s.isEmpty() }.makeString("\n")
+    message = message.lines().map { it.trimEnd() }.filterNot { it.isEmpty () }.joinToString("\n")
     return message
 }