SI-4360 Adds prefixes to scaladoc

This was a long-standing issue in scaladoc: It was unable to
disambiguate between entries with the same name. One example is:
immutable.Seq:

trait Seq[+A] extends Iterable[A] with Seq[A] ...

What's that? Seq extends Seq? No, immutable.Seq extends collection.Seq,
but scaladoc was unable to show that. Now it does, depending on the
template you're in. Prefixes are relative and can go back:
-scala.collection.Seq has subclasses *immutable.Seq* and *mutable.Seq*
-scala.immutable.Seq extends *collection.Seq*

Unfortunately the price we pay for this is high, a 20% slowdown in
scaladoc. This is why there is a new flag called -no-prefixes that
disables the prefixes in front of types.

Btw, it also fixes the notorious "booleanValue: This member is added by
an implicit conversion from Boolean to Boolean ...". That's now
java.lang.Boolean, so it becomes clear.

Conflicts:

	src/compiler/scala/tools/nsc/doc/model/diagram/DiagramFactory.scala

1 files changed, 1 insertions, 0 deletions

diff --git a/test/scaladoc/run/SI-4360.check b/test/scaladoc/run/SI-4360.check
new file mode 100644
index 0000000000..619c56180b
--- /dev/null
+++ b/test/scaladoc/run/SI-4360.check
@@ -0,0 +1 @@
+Done.