Add type printer to properly handle Kotlin style null syntax

This CL updates the handling of Kotlin-style null syntax (used
in format v3). It now does a much more accurate job formatting
types from Java syntax (and Java type use annotation syntax)
into Kotlin-style nullness syntax. This cannot be done with
simple things like replacing @Nullable with ? since the place
for the annotations in the type expression is not the same as
where the nullness suffix goes.

This CL also adds --format=latest as an alias for --format=v3
and --format=recommended as an alias for --format=v2.
(The alias values will change over time as the formats and
recommendations evolve.)

Bug: 123415058
Test: Many new unit tests
Change-Id: I6622041f0966b99157db4fe60d534a55e658bd10