Create new doc page for Literal Singleton Types

Author: Varunram

docs/docs/reference/singleton-types.md

@@ -0,0 +1,20 @@
+---
+layout: doc-page
+title: "Literal Singleton Types"
+---
+
+Literal Singleton Types allows primitive literals to be used as types. For example:
+
+```scala
+val t: 42 = 42
+val t: "Jedi" = "Jedi"
+```
+
+It is also possible to define functions returning or taking singleton types such as
+
+```scala
+def f(t: Double): t.type = t
+val a: 1.2 = f(1.2)
+```
+
+For more details and the motivation behind the need for literal singleton types, check out [SIP-23](http://docs.scala-lang.org/sips/pending/42.type.html)