Print anonymous namespaces as <anonymous namespace> instead of <anonymous>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@201436 91177308-0d34-0410-b5e6-96231b3b80d8
Consistently print anonymous namespace names as "<anonymous namespace>"

For some reason we have two bits of code handling this printing:

lib/AST/Decl.cpp:        OS << "<anonymous namespace>";
lib/AST/TypePrinter.cpp:      OS << "<anonymous namespace>::";

it would be nice if we only had one...

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@201437 91177308-0d34-0410-b5e6-96231b3b80d8