Merge pull request scala#10376 from xuwei-k/SimpleTracer-scaladoc

fix `SimpleTracer` scaladoc

Author: lrytz

src/compiler/scala/tools/nsc/util/SimpleTracer.scala

@@ -18,8 +18,8 @@ package util
 import java.io.PrintStream
 
 /** A simple tracer
- *  @param out: The print stream where trace info should be sent
- *  @param enabled: A condition that must be true for trace info to be produced.
+ *  @param out The print stream where trace info should be sent
+ *  @param enabled A condition that must be true for trace info to be produced.
  */
 class SimpleTracer(out: PrintStream, enabled: Boolean = true) {
   def apply[T](msg: => String)(value: T): T = {