Fix doc comment

Author: odersky

src/dotty/tools/dotc/reporting/ThrowingReporter.scala

@@ -7,7 +7,8 @@ import collection.mutable
 import Reporter._
 
 /**
- * This class implements a Reporter that stores all messages
+ * This class implements a Reporter that throws all errors and sends warnings and other
+ * info to the underlying reporter.
  */
 class ThrowingReporter(reportInfo: Reporter) extends Reporter {
   protected def doReport(d: Diagnostic)(implicit ctx: Context): Unit = d match {