Fix #9102: printing of by-name params in the repl

[december32]

By-name param types are printed correctly in the repl now:

scala> def foo(x: => Int) = x.toString
def foo(x: => Int): String

scala> foo                                                                     
val res0: (=> Int) => String = Lambda$8017/710782087@713e0527

scala> def bar: (=> Int) => String = x => x.toString                           
def bar: (=> Int) => String

scala> bar                                                                     
val res1: (=> Int) => String = Lambda$8031/1337976273@91c70f7

[dottybot]

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[odersky]

Thank you for the fix.