`reveal_type` should print out nice formatted types

Extracted from #6460

Say you have

lx: Optional[Tuple[str, int]] = None
lx[0]
reveal_type(lx)

mypy outputs

Value of type "Optional[Tuple[str, int]]" is not indexable
Revealed type is 'Union[Tuple[builtins.str, builtins.int], None]'

As you can see (and probably know) it shows two different representations for the inferred type. For user ergonomics the revealed type should be 'Optional[Tuple[int, str]]' as well, no?

The maybe too naive but works for me change is

@@ -1051,7 +1051,7 @@ class MessageBuilder:
         self.fail('Invalid signature "{}" for "{}"'.format(func_type, method_name), context)
 
     def reveal_type(self, typ: Type, context: Context) -> None:
-        self.fail('Revealed type is \'{}\''.format(typ), context)
+        self.fail('Revealed type is {}'.format(self.format(typ)), context)
 
     def reveal_locals(self, type_map: Dict[str, Optional[Type]], context: Context) -> None:
         # To ensure that the output is predictable on Python < 3.6,

But then you get 1.000.000 failures which is expected because the tests rely on the verbose output.

E.g.

Expected:
  main:10: error: Revealed type is 'builtins.int' (diff)
  main:11: error: Revealed type is 'Tuple[builtins.int, builtins.int]' (diff)
  main:13: error: Revealed type is 'Literal[1]' (diff)
  main:14: error: Argument 1 to "force2" has incompatible type "Tuple[int, in...
  main:14: error: Revealed type is 'Tuple[builtins.int, builtins.int]' (diff)
Actual:
  main:10: error: Revealed type is "int"        (diff)
  main:11: error: Revealed type is "Tuple[int, int]" (diff)
  main:13: error: Revealed type is "Literal[1]" (diff)
  main:14: error: Argument 1 to "force2" has incompatible type "Tuple[int, in...
  main:14: error: Revealed type is "Tuple[int, int]" (diff)

This makes it a non-trivial change.

Comienza en MessageBuilder.reveal_type, donde el issue muestra la construcción actual de la salida, y compárala con la salida de tipo formateada existente. Actualiza las expectativas afectadas de reveal_type en todo el conjunto de pruebas para que los tipos revelados usen el formato visible para el usuario y, después, ejecuta las pruebas de mypy para confirmar los diagnósticos revisados.