delete or update `scala-reflect` scaladoc link in `rootdoc.txt`

[xuwei-k]

Compiler version

3.8.0-RC1

Description

• scala3/library/src/rootdoc.txt

  Line 34 in 91351e3

  - [[https://www.scala-lang.org/api/current/scala-reflect/scala/reflect/index.html `scala.reflect`]] - Scala's reflection API (scala-reflect.jar)

• Fix scala-reflect scaladoc link scala#11184