Adjust unknown macro error message

Adjust unknown macro error message

gcc/rust/ChangeLog:

	* resolve/rust-early-name-resolver-2.0.cc
	(Early::visit): Adjust error produced when macro resolution
	fails.
	* resolve/rust-early-name-resolver.cc
	(EarlyNameResolver::visit): Likewise.

gcc/testsuite/ChangeLog:

	* rust/compile/macros/mbe/macro43.rs: Adjust expected errors.
	* rust/compile/macros/mbe/macro44.rs: Likewise.
	* rust/compile/nested_macro_use2.rs: Likewise.
	* rust/compile/nr2/exclude: Remove entries.

Signed-off-by: Owen Avery <powerboat9.gamer@gmail.com>