SI-9140 Allow omitting pleonastic parameter name

Enable simply:

```
scala> def f(@deprecatedName foo: String) = foo.reverse
f: (foo: String)String

scala> f(foo = "bar")
<console>:9: warning: naming parameter foo has been deprecated.
              f(foo = "bar")
                    ^
res0: String = rab
```

`Symbol.deprecatedParamName` conventionally returns `NO_NAME`
when the name is omitted.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/library/scala/deprecatedName.scala b/src/library/scala/deprecatedName.scala
index 07c5c8925c..a0d3aa829b 100644
--- a/src/library/scala/deprecatedName.scala
+++ b/src/library/scala/deprecatedName.scala
@@ -29,4 +29,6 @@ import scala.annotation.meta._
  * @since 2.8.1
  */
 @param
-class deprecatedName(name: Symbol) extends scala.annotation.StaticAnnotation
+class deprecatedName(name: Symbol) extends scala.annotation.StaticAnnotation {
+  def this() = this(Symbol("<none>"))
+}