Scripting: notify writer in REPL on errors reporting complete

required for restoring compatibility with IDE REPL usages (scratch
files included), since IDE counterpart needs a reliable signal
when the processing of the REPL snippet/command is completed

compiler/util/src/org/jetbrains/kotlin/utils/repl/ReplEscapeType.kt

@@ -27,6 +27,8 @@ enum class ReplEscapeType {
     COMPILE_ERROR,
     RUNTIME_ERROR,
     INTERNAL_ERROR,
+    ERRORS_REPORTED, // should be send after reporting all errors caused by the current command
+                     // e.g. IDE uses it to recognize the end of command processing
     SUCCESS;
 
     companion object {