name overrides

[Tsche]

Tests should respect rsl::preferred_name overrides. Need to consolidate this with rsl::rename.

preferred_name should also work for namespaces. It might be desirable to rename a testing namespace, ie

// code to be tested
namespace zoinks {
  struct Foo;
}

// tests
namespace zoinks {
namespace [[=rsl::preferred_name("Foo")]] _test_foo {
[[=rsl::test]]
void test_something() { /* ... */ }
}
}

should report the test's name as zoinks::Foo::test_something rather than zoinks::_test_foo::test_something.