Rollup merge of #120693 - nnethercote:invert-diagnostic-lints, r=davidtwco

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 been converted to use translated diagnostics.

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

r? ````@davidtwco````

src/librustdoc/lib.rs

@@ -18,7 +18,9 @@
 #![recursion_limit = "256"]
 #![warn(rustc::internal)]
 #![allow(clippy::collapsible_if, clippy::collapsible_else_if)]
+#![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::potential_query_instability)]
+#![allow(rustc::untranslatable_diagnostic)]
 
 extern crate thin_vec;
 #[macro_use]