GreatSyntacticShift: Syntax for function types, function literals, when and tuples

Bug:
fun loop(var times : Int) {
   while(times > 0) {
        val u : (value : Int) -> Unit = { // This arrow is confusing the lookahead
            System.out?.println(it)
        }
        u(times--)
   }
}

compiler/testData/diagnostics/tests/Basic.jet

@@ -2,7 +2,7 @@ fun foo(<!UNUSED_PARAMETER!>u<!> : Unit) : Int = 1
 
 fun test() : Int {
     foo(<!TYPE_MISMATCH!>1<!>)
-    val <!UNUSED_VARIABLE!>a<!> : fun() : Unit = {
+    val <!UNUSED_VARIABLE!>a<!> : () -> Unit = {
         foo(<!TYPE_MISMATCH!>1<!>)
     }
     return 1 <!NONE_APPLICABLE!>-<!> "1"