gccrs: Add name resolution to generic argument associated item bindings

gccrs: Add name resolution to generic argument associated item bindings

When specifying generic arguments to Traits we can also specify the
associated types using `<BindingName=i32>` syntax we need to add
name resolution to the type argument here and rely on the type
resolution pass to ensure the associated type exists and to setup the
associated types accordingly.

Addresses #1720

gcc/rust/ChangeLog:

	* resolve/rust-ast-resolve-type.cc (ResolveGenericArgs::go): Add name resolution to
	Trait items.

Signed-off-by: Philip Herron <herron.philip@googlemail.com>