Export does not export @alpha name

```Scala
object Foo:
  @scala.annotation.alpha("w") def \/\/ = "W"

object Bar:
  export Foo._
```
```scala
// Java decompiled Foo method signature
public String w() 

// Java decompiled Bar method signature, should be same as above
public final String $bslash$div$bslash$div()

```
