Print nested name specifiers for typedefs and type aliases

Print nested name specifiers for typedefs and type aliases

Printing typedefs or type aliases using clang_getTypeSpelling() is missing the
namespace they are defined in. This is in contrast to other types that always
yield the full typename including namespaces.

Patch by Michael Reiher!

Differential Revision: https://reviews.llvm.org/D29944

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@297465 91177308-0d34-0410-b5e6-96231b3b80d8