gccrs: libproc_macro: Remove internal named namespaces

gccrs: libproc_macro: Remove internal named namespaces

Either move the elements from their namespace up to the procmacro
namespace or make the namespace anonymous.

libgrust/ChangeLog:

	* libproc_macro/group.cc (Group::make_group): Remove
	internal namespace.
	(Group::drop): Likewise.
	* libproc_macro/group.h (enum Delimiter): Make members
	upercase.
	(struct Group):
	* libproc_macro/ident.cc (Ident::drop): Remove internal
	namespace.
	* libproc_macro/ident.h (Ident__clone): Likewise.
	* libproc_macro/literal.cc (Literal::make_isize):
	Likewise.
	* libproc_macro/literal.h (union LiteralPayload):
	Likewise.
	(Literal__from_string): Likewise.
	* libproc_macro/punct.cc (Punct::make_punct): Likewise.
	* libproc_macro/punct.h (enum Spacing): Make members
	uppercase.
	* libproc_macro/tokenstream.cc (TokenStream::make_tokenstream):
	Remove internal namespace.
	(TokenStream::grow): Likewise.
	(TokenStream::push): Likewise.
	(TokenSream__push): Likewise.
	(TokenStream__clone): Likewise.
	(TokenStream__drop): Likewise.
	* libproc_macro/tokenstream.h (struct TokenStream):
	Likewise.
	(TokenSream__push): Likewise.
	(TokenStream__drop): Likewise.
	* libproc_macro/tokentree.cc (TokenTree::make_tokentree):
	Likewise.
	(TokenTree::drop): Likewise.
	* libproc_macro/tokentree.h (union TokenTreePayload):
	Likewise.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>