gccrs: Add call to globbing visitor

gccrs: Add call to globbing visitor

Globbing visitor did not visit subitems.

gcc/rust/ChangeLog:

	* resolve/rust-late-name-resolver-2.0.cc (Late::visit): Add a check
	for missing item.
	* resolve/rust-toplevel-name-resolver-2.0.cc (GlobbingVisitor::go):
	Add a new function in the visitor to dispatch the visitor to items in
	the given module.
	(TopLevel::handle_use_glob): Change call to visitor to use the pointer.
	* resolve/rust-toplevel-name-resolver-2.0.h: Add prototype for new
	member function.

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