Invert diagnostic lints.

That is, change `diagnostic_outside_of_impl` and
`untranslatable_diagnostic` from `allow` to `deny`, because more than
half of the compiler has be converted to use translated diagnostics.

This commit removes more `deny` attributes than it adds `allow`
attributes, which proves that this change is warranted.

compiler/rustc_resolve/src/lib.rs

@@ -17,7 +17,9 @@
 #![feature(let_chains)]
 #![feature(rustc_attrs)]
 #![allow(rustdoc::private_intra_doc_links)]
+#![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::potential_query_instability)]
+#![allow(rustc::untranslatable_diagnostic)]
 #![allow(internal_features)]
 
 #[macro_use]