Working test cases for the sophisticated matrix library example from the manual

Fixed the dot operator when used within return types (see tgenericdotrettype)
Fixed the matching of generic concepts aliases used with the implicit generics style

tests/generics/tgenericdotrettype.nim

@@ -0,0 +1,29 @@
+discard """
+output: '''string
+int
+(int, string)
+'''
+"""
+
+import typetraits
+
+type
+  Foo[T, U] = object
+    x: T
+    y: U
+
+proc bar[T](a: T): T.U =
+  echo result.type.name
+
+proc bas(x: auto): x.T =
+  echo result.type.name
+
+proc baz(x: Foo): (Foo.T, x.U) =
+  echo result.type.name
+
+var
+  f: Foo[int, string]
+  x = bar f
+  z = bas f
+  y = baz f
+